What’s the lowest tyre pressure that’s sensable for a Tandem

[PeterCarole29]

We previously had a Tandem with front fork suspension and 26” wheels and never really noticed bad road vibration
Now I have 20” wheels no front suspension and fitted schwalbe marathon tyres and swytch electric kit over powered front wheel tyre pressure left high which I realise was too hard as test drive was awful terrible vibration
Being a novice thought I would ask what’s the lowest pressure I can sensibly go to and the I could work upwards from there
Cables not secure yet in photo but we’re on test drive

 

[mapman]

No experience of that set up but I have found that too low a pressure invites pinch punctures. Given the weight of bike, motor, plus two riders I would work the other way. Start at the recommended max pressure for the tyres and reduce by say 5 psi and see how they cope with sudden changes in surface like potholes and curbs. Even when running 27” wheels at 100 psi on regular bike I had pinch punctures a few times. I now run tubeless - you can run at lower pressure and no punctures to date.

 

[Lyrick]

We have the same bike and keep the tyre pressures at 55 psi, which is 10 psi below the maximum stated on the tyre walls. The tyres are the originals that came with the bike. Same set up with a front electric hub, not a Swytch though.

We've done a few hundred miles on it without any vibration . Could it be the motor causing the problem ?

 

[PeterCarole29]

No experience of that set up but I have found that too low a pressure invites pinch punctures. Given the weight of bike, motor, plus two riders I would work the other way. Start at the recommended max pressure for the tyres and reduce by say 5 psi and see how they cope with sudden changes in surface like potholes and curbs. Even when running 27” wheels at 100 psi on regular bike I had pinch punctures a few times. I now run tubeless - you can run at lower pressure and no punctures to date.

Thanks

 

[PeterCarole29]

We have the same bike and keep the tyre pressures at 55 psi, which is 10 psi below the maximum stated on the tyre walls. The tyres are the originals that came with the bike. Same set up with a front electric hub, not a Swytch though.

We've done a few hundred miles on it without any vibration . Could it be the motor causing the problem ?

Thanks the pressure I test road it at was 65psi and as said earlier will work down from that and see how it rides I have also altered the home made brackets the swytch kit is mounted to as it was flexing which also contributed to the vibration being extenuated

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[suavecarve]

I have a 20 inch wheeled electric tandem, make sure you have spare spokes !

 

[Guigsy]

I've got a Brompton that I run 100psi, and my mountain bike runs 17psi... It mainly depends on the tyre volume.

 

[Aireworth]

It depends on the width of the tyre, as well as the circumference - as Guigsy says the volume. What's sensible also depends on the weight of the bike + rider(s). What is the width - it'll say on the tyre wall 20 x something. There will also be an ETRTO number which give the same information but in a standardised metric form. There are sites which will give you ranges for the tyre size and the weight of the bike plus riders. Post the details here and I'll check, if you want.

 

[Guigsy]

It depends on the width of the tyre, as well as the circumference - as Guigsy says the volume. What's sensible also depends on the weight of the bike + rider(s). What is the width - it'll say on the tyre wall 20 x something. There will also be an ETRTO number which give the same information but in a standardised metric form. There are sites which will give you ranges for the tyre size and the weight of the bike plus riders. Post the details here and I'll check, if you want.

As with car tyres, the pressure stamped on the carcass is the maximum. You probably want to run quite a lot lower.

 

[PeterCarole29]

It depends on the width of the tyre, as well as the circumference - as Guigsy says the volume. What's sensible also depends on the weight of the bike + rider(s). What is the width - it'll say on the tyre wall 20 x something. There will also be an ETRTO number which give the same information but in a standardised metric form. There are sites which will give you ranges for the tyre size and the weight of the bike plus riders. Post the details here and I'll check, if you want.

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[PeterCarole29]

It depends on the width of the tyre, as well as the circumference - as Guigsy says the volume. What's sensible also depends on the weight of the bike + rider(s). What is the width - it'll say on the tyre wall 20 x something. There will also be an ETRTO number which give the same information but in a standardised metric form. There are sites which will give you ranges for the tyre size and the weight of the bike plus riders. Post the details here and I'll check, if you want.

Thankyou that would be good
Front rider me 11 stone wife is 8 stone bike with electric kit is 38kg
20” x 1.75 on a 406 rim

 

[PeterCarole29]

I have a 20 inch wheeled electric tandem, make sure you have spare spokes !

I had wondered about the strength of my spokes
On our last Tandem because we had to remove the front wheel to mount on the back of the camper i once forgot to put the front wheel in the van and drove off with out it,it was only a week old and lesson learnt. but the result was when i bought a new wheel the shop said i really ought to buy a wheel fit for a tandem with thicker spokes so i ended up buying front and back.
I,m hoping the front wheel supplied by swytch being electric will be fit for purpose just leaving the back end to consider at a later date

 

[PeterCarole29]

Its been a long time since i messed with push bikes 50yrs and had forgot everything
so far learnt to date . Also forgot how much you can spend on upgrades
Pedals are markes Left and Right got that wrong
one pedal got croosed threaded as the pedal had a dent on the thread posibly also as i started with the wrong pedal. So a thread tap ordered
New seat posts with suspension in them x 2
silocone seats x 2
Better tyres x 2

 

[Terry242]

A FRIGHTENING TANDEM TALE.

We were travelling in Germany when I got into conversation with a motorhomer pitched behind us. It turned out the motorhome had been loaned to him buy his insurance company after he and his wife had an accident on a tandem.

The couple were from New Zealand and were on a 3 month tour of Germany backpacking with there tandem. They had completed a previous tour on their old tandem but for this tour they had swapped their old heavy bike for the latest in lightweight kit.

On their 1st week touring they were going down a steep mountain decent. He was braking hard when they suffered a front wheel blowout which sent both of them into the scenery! He was quite badly injured whilst his wife was lucky and had just bumps and bruises. He explained the accident by saying that the lightweight wheels had been too lightweight and with a prolonged period of heavy braking, the lightweight wheel had transferred heat to the tube causing the blowout!

He spent 2weeks in a German hospital but was too injured to fly home so their insurance company provided a motorhome and they had been touring for about 6 weeks whilst he was recovering. He was due to return to hospital that week to be signed off so that they could fly home.

Terry

 

[PeterCarole29]

A FRIGHTENING TANDEM TALE.

We were travelling in Germany when I got into conversation with a motorhomer pitched behind us. It turned out the motorhome had been loaned to him buy his insurance company after he and his wife had an accident on a tandem.

The couple were from New Zealand and were on a 3 month tour of Germany backpacking with there tandem. They had completed a previous tour on their old tandem but for this tour they had swapped their old heavy bike for the latest in lightweight kit.

On their 1st week touring they were going down a steep mountain decent. He was braking hard when they suffered a front wheel blowout which sent both of them into the scenery! He was quite badly injured whilst his wife was lucky and had just bumps and bruises. He explained the accident by saying that the lightweight wheels had been too lightweight and with a prolonged period of heavy braking, the lightweight wheel had transferred heat to the tube causing the blowout!

He spent 2weeks in a German hospital but was too injured to fly home so their insurance company provided a motorhome and they had been touring for about 6 weeks whilst he was recovering. He was due to return to hospital that week to be signed off so that they could fly home.

Terry

An informative story to bear in mind
Although we are not enthusiastic bike riders that my wife is comfortable at 12mph poodlig along its worth being cautious down hills

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[Aireworth]

Thankyou that would be good
Front rider me 11 stone wife is 8 stone bike with electric kit is 38kg
20” x 1.75 on a 406 rim

I've been stymied, I'm afraid. The site I was using doesn't go lower than 26in. Sorry. I'll keep looking.

 

[Aireworth]

A FRIGHTENING TANDEM TALE.

We were travelling in Germany when I got into conversation with a motorhomer pitched behind us. It turned out the motorhome had been loaned to him buy his insurance company after he and his wife had an accident on a tandem.

The couple were from New Zealand and were on a 3 month tour of Germany backpacking with there tandem. They had completed a previous tour on their old tandem but for this tour they had swapped their old heavy bike for the latest in lightweight kit.

On their 1st week touring they were going down a steep mountain decent. He was braking hard when they suffered a front wheel blowout which sent both of them into the scenery! He was quite badly injured whilst his wife was lucky and had just bumps and bruises. He explained the accident by saying that the lightweight wheels had been too lightweight and with a prolonged period of heavy braking, the lightweight wheel had transferred heat to the tube causing the blowout!

He spent 2weeks in a German hospital but was too injured to fly home so their insurance company provided a motorhome and they had been touring for about 6 weeks whilst he was recovering. He was due to return to hospital that week to be signed off so that they could fly home.

Terry

Another reason for disc brakes, and tubeless tyres.

 

[clanjones]

So we use 700 x 28 mm hand built tandem wheels (40 double butted spokes) on continental Gator skin tyres and generally run them at 100psi. We do have carbon front forks ( hence the reason for from v brakes) and handle bars, which does dampen the vibration.

We have a 203mm rear disc and front v brakes. Yep we have had front blow outs on descents and they have been generally due to rim tape issues which with the heat causes the end of the spokes to puncture the inner tube. We now double the rim tape and don't have that issue.

Always managed to stop safely - long may it continue!

 

[Aireworth]

So we use 700 x 28 mm hand built tandem wheels (40 double butted spokes) on continental Gator skin tyres and generally run them at 100psi. We do have carbon front forks ( hence the reason for from v brakes) and handle bars, which does dampen the vibration.

We have a 203mm rear disc and front v brakes. Yep we have had front blow outs on descents and they have been generally due to rim tape issues which with the heat causes the end of the spokes to puncture the inner tube. We now double the rim tape and don't have that issue.

Always managed to stop safely - long may it continue!

Deleted - I was wrong!

 

[Lyrick]

Its been a long time since i messed with push bikes 50yrs and had forgot everything
so far learnt to date . Also forgot how much you can spend on upgrades
Pedals are markes Left and Right got that wrong
one pedal got croosed threaded as the pedal had a dent on the thread posibly also as i started with the wrong pedal. So a thread tap ordered
New seat posts with suspension in them x 2
silocone seats x 2
Better tyres x 2

In the process of building another one with a rear hub motor. On this bike I've found quite a few bolts/nuts not fully tightened/loose. Might be worth checking yours.

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[clanjones]

Just some experience of tubeless. On a long trip we did last year (1750 Miles) one of the guys on a solo used tubeless tires and in his words, fine for day trips, but for extended touring never again. He had no end of issues and ended up with a tube inside! I am not trying to start a debate on tubeless versus tubed - it is horse for courses. If you are happy with your set up stick with it!

We have ridden thousands of miles on the tandem with very few issues in some quite remote areas and my main concern is that I can always repair a puncture on a tubed tire.

We do get punctures but not that many but when a Gator skin costs £40.00 (I can hear the "How Much chorus"!) then hopefully we shouldn't get many! As an side we also carry CO2 cartridges to inflate the tyres and these are a godsend when trying to get to 100 psi! In my view they are essential. They are also sooo much quicker.

Right that’s me off to finish repairing the bike box that Easyjet so kindly damaged!

 

[PeterCarole29]

Just some experience of tubeless. On a long trip we did last year (1750 Miles) one of the guys on a solo used tubeless tires and in his words, fine for day trips, but for extended touring never again. He had no end of issues and ended up with a tube inside! I am not trying to start a debate on tubeless versus tubed - it is horse for courses. If you are happy with your set up stick with it!

We have ridden thousands of miles on the tandem with very few issues in some quite remote areas and my main concern is that I can always repair a puncture on a tubed tire.

We do get punctures but not that many but when a Gator skin costs £40.00 (I can hear the "How Much chorus"!) then hopefully we shouldn't get many! As an side we also carry CO2 cartridges to inflate the tyres and these are a godsend when trying to get to 100 psi! In my view they are essential. They are also sooo much quicker.

Right that’s me off to finish repairing the bike box that Easyjet so kindly damaged!

Thanks everyones experience is helpful. Although we are day trippers so to speak i do like to limit any mishaps or breakdowns which is why i have gone for the marathon tyres but £29 each they aparently have some punture protection i also was sold an inner tube with goo in whick i have put on the front electric wheel. ( This may or may not have been a mistake) I will however when we go for a bike ride take a punture kit, spare inner tube, and pump so we can at least get back to the camp site

 

[clanjones]

Marathon tyres are a good quality robust tyre and will cope with more trail type riding than the gators!

We always take 2 inner tubes with us, for the weight difference it gives us peace of mind and we have had to use both with in the space of 30 minutes!

 

[CA]

I worked as a pro bike mechanic (previous life; no longer!); not in bike shops but for semi pro events and tours like the RAAM (Race across America) and also supported tours like the Tour de France. One thing I note that almost all non professional cyclists run their tyres at too higher pressure.

Tyres are your primary suspension. Studies show that too high a pressure on your tyre means that you, the rider, need to absorb all the small micro bumps and road inadequacies. This makes you very fatigued. And thus making cycling over a long distance a huge chore and slow you down. You will go faster if you have lower tyre pressures.

An example would be a brompton tyre. The tyre itself will say 100 or 110psi max. You should be no where near this! Around 60psi is where this tyre should be. Obviously different factors include your weight, the type of surface you ride on, the amount of luggage and so on. And you adjust upwards if you are adding a lot of weight.

Oh - and rear should be slightly higher pressure than your front…

Some ‘light’ reading on the matter:

Suspension Losses Confirmed

Recently, Bicycle Quarterly's experiments on suspension losses have been replicated and confirmed: Higher tire pressures don't result in faster speeds – even on smooth pavement. Replicating results is a crucial part of science, which makes the new results an important milestone in the...

www.renehersecycles.com

Myths Debunked: Wide Tires Are NOT Slower

When we started to publish Bicycle Quarterly 15 years ago, it seemed that most of the technical aspects of bicycles were well-known. And yet, as we tested many different bikes, we started to question many of the things we had accepted as 'facts.' To celebrate…

www.renehersecycles.com

And some general starting point recommendations-

700c TYRE SIZE
| Recommended | Absolute
| FRONT REAR | MAX MIN
23c | 108 118 | 130 85
25c | 100 110 | 120 75
28c | 88 95 | 105 65
32c | 70 75 | 90 55
35c | 60 65 | 80 45
38c | 53 58 | 75 40
40c | 48 53 | 70 35

26" TYRE SIZE
| Recommended | Absolute
| FRONT REAR | MAX MIN
1.35" | 60 65 | 80 45
1.60" | 48 53 | 70 35
1.75" | 45 50 | 65 32
2.00" | 40 45 | 58 30
2.10" | 38 43 | 54 28
2.25" | 35 40 | 50 26
2.35" | 32 37 | 48 24

 

[PeterCarole29]

I worked as a pro bike mechanic (previous life; no longer!); not in bike shops but for semi pro events and tours like the RAAM (Race across America) and also supported tours like the Tour de France. One thing I note that almost all non professional cyclists run their tyres at too higher pressure.

Tyres are your primary suspension. Studies show that too high a pressure on your tyre means that you, the rider, need to absorb all the small micro bumps and road inadequacies. This makes you very fatigued. And thus making cycling over a long distance a huge chore and slow you down. You will go faster if you have lower tyre pressures.

An example would be a brompton tyre. The tyre itself will say 100 or 110psi max. You should be no where near this! Around 60psi is where this tyre should be. Obviously different factors include your weight, the type of surface you ride on, the amount of luggage and so on. And you adjust upwards if you are adding a lot of weight.

Oh - and rear should be slightly higher pressure than your front…

Some ‘light’ reading on the matter:

Suspension Losses Confirmed

Recently, Bicycle Quarterly's experiments on suspension losses have been replicated and confirmed: Higher tire pressures don't result in faster speeds – even on smooth pavement. Replicating results is a crucial part of science, which makes the new results an important milestone in the...

www.renehersecycles.com

Myths Debunked: Wide Tires Are NOT Slower

When we started to publish Bicycle Quarterly 15 years ago, it seemed that most of the technical aspects of bicycles were well-known. And yet, as we tested many different bikes, we started to question many of the things we had accepted as 'facts.' To celebrate…

www.renehersecycles.com

And some general starting point recommendations-

700c TYRE SIZE
| Recommended | Absolute
| FRONT REAR | MAX MIN
23c | 108 118 | 130 85
25c | 100 110 | 120 75
28c | 88 95 | 105 65
32c | 70 75 | 90 55
35c | 60 65 | 80 45
38c | 53 58 | 75 40
40c | 48 53 | 70 35

26" TYRE SIZE
| Recommended | Absolute
| FRONT REAR | MAX MIN
1.35" | 60 65 | 80 45
1.60" | 48 53 | 70 35
1.75" | 45 50 | 65 32
2.00" | 40 45 | 58 30
2.10" | 38 43 | 54 28
2.25" | 35 40 | 50 26
2.35" | 32 37 | 48 24

Thanks thank very informative I did try our 20" tandem tyres at 65psi but the ride was awful we have also go inner tubes in.
It has been mentioned earlier to be aware or tyre pintching puntures would you have any experience of what pressure would be unwise to go down too, as i have no experiance of push bike tyres only motorcross and enduro and we had tyre clamps then and foam inner tubes
Our Tamden tyres i have fitted are Schwable The Green Marathon 20 x 1.75
Many thanks Peter

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[CA]

Thanks thank very informative I did try our 20" tandem tyres at 65psi but the ride was awful we have also go inner tubes in.
It has been mentioned earlier to be aware or tyre pintching puntures would you have any experience of what pressure would be unwise to go down too, as i have no experiance of push bike tyres only motorcross and enduro and we had tyre clamps then and foam inner tubes
Our Tamden tyres i have fitted are Schwable The Green Marathon 20 x 1.75
Many thanks Peter

I would say intitally dropping to 55psi would be a good starting point.
This online calculator may help - https://www.renehersecycles.com/tire-pressure-calculator/

Use the above link as a guide - not a strict code to religiously follow.
When I tour on bikes I adjust the pressure occasionally depending in the road surfaces. And also obviously depending on the weight load; your tandem is going to be heavier so yes you need to be mindful not to drop too low. But as I said, most people run tires way too high.

Avoiding pinch flats - 1. correct preseure (use the guide above). 2. Run wider tyres if your bike can take them. 3. Avoid holes/curbs/rocks (adjust preseures to the surface you are riding on - a nice smooth french road is diffrent from the pamir highway! Or a uk road…) 4. Go tubeless.

 

[clanjones]

Just stuck in our combined weight for 28mm tires and what do you know 100 PSI !!

 

[Guigsy]

I'm coming up to 10,000km on my 3 year old Specialized Diverge gravel bike. It's been on tubeless since day 1. It's heavily abused. I've had 3 punctures. Two were with a Teravail tyre with a paperthin sidewall at a race in Wales that was mostly on flint. Sealant doesn't cover the sidewalls that well... The other was a huge shard of glass that the sealant wouldn't fill until I pulled it out and shoved a bacon strip in the gash.

My mate got the same bike at the same time. He refused to convert to tubeless. Until this year when he had 4 punctures in one race. And after he bike packed to John O'Groats and punctured at least once every day.

Meanwhile I've done 1,500km on my commuter bike in the year I've had it. It's ridden much more gently. But I've had 6 punctures using inner tubes. I'd convert it if I could.

My mountain bikes... Never had a puncture since going tubeless. Although one time I was running such low pressure I burped the tyre on a big rock, then nearly rolled the tyre off the rim on the next corner and sprayed sealant everywhere.

 

[PeterCarole29]

As a total novice
So running tubeless you have sealant inside so the tyre gets pearced but gets sealed straight away
Can you run tubeless at say 40 psi

 

[Guigsy]

As a total novice
So running tubeless you have sealant inside so the tyre gets pearced but gets sealed straight away
Can you run tubeless at say 40 psi

The rim and the tyre have to be tubeless compatible. Then, instead of using a skinny innertube to contain your air, you use the thick tyre carcass. The sealant fills the gaps and the vast majority of punctures without you even noticing. Run over a hawthorn branch with inch long thorns? No problem, you might just lose a psi or two while the sealant rasps out for a couple of seconds.

Setting up tubeless can be a pain. And it does loose air a little more quickly than a tube. The sealant does dry up everyday. If you're only using the bike occasionally, it's probably not worth it. But for regular rides, it's way better than tubes.

Also, lower pressures, more comfortable, but less rolling resistance. Win-win.

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