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Thread: Tire Pressure

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    Tire Pressure

    Hi,

    We just purchased a Santana Tandem with the Ultra Gatorskins 700x25. The folks at Santana said we should run them at 140 PSI even though the max recommended is 120 psi. I'd sure hate to blow a tire due to too much pressure, but also don't want to pinch flat. Not sure if it makes any difference, but our combined weight is 325lbs. Any thoughts would be appreciated.
    Thanks

  2. #2
    Bill G Bill G's Avatar
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    I run the Michelin Pro Race 2 Tires in 700x25C on our Co-Motion Robusta, the tire measures more like a 700x27C, the Michelin 700x25C tires run a little larger in size than what the sidewall states. Dewan the owner of Co-Motion recommended this tire to me for my needs and recommended 130 PSI even though the tire said max inflation of 106 PSI on the sidewall. I have had no problems what so ever. I ran 130 to 135 PSI in my 700x28C Conti Ultra Gater Skins (the sidwalls said 120PSI max) with no problems as well. With a tandem you have to run a little higher pressure in the tires to prevent pinch flats and for proper tire performance on a tandem. The smaller the tire size used such as a 700x23C or 700x25C a higher pressure is needed to prevent pinch flats and to improve tire performance in a tandem application.. Me and the wife weigh in at about a 340lb to 345lbs plus 30lbs for the tandem.

    There is a great article on tires and tire inflation at Precision Tandems web site www.precisiontandems.com the article is on the left side of there main page. The article has a chart or graph specific to tandems tire size, team weight, and air pressure needed for tire size and total team weight. This chart is worth taking a look at. (the article is a good read)

    Good luck,
    Bill G
    Last edited by Bill G; 09-04-06 at 06:10 PM.
    Co-Motion Custom Primera Tandem (AKA The Marrage Counselor)
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    Senior Member Retro Grouch's Avatar
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    My wife and I weigh significantly more than you do. We use use 28mm gatorskins @110psi rear and 100psi front and don't pinch flat.

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    Bill G Bill G's Avatar
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    Quote Originally Posted by Retro Grouch
    My wife and I weigh significantly more than you do. We use use 28mm gatorskins @110psi rear and 100psi front and don't pinch flat.

    We found performance to be better with the Conti 28mm gaterskins inflated to around 125 to 130 PSI and we weigh in at 340lbs to 345lbs as a team plus 30 lbs for the tandem.

    Take Care,
    Bill G
    Co-Motion Custom Primera Tandem (AKA The Marrage Counselor)
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    Thanks

    Thanks for the good info. The article was very helpful. Sounds like we should have considered 700x28 instead of 25. It may be that the sweet 16 wheels should be running 700x25. I'll have to check and see what they say.

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    I run Conti 4000 700x23s at 120psi. team weight about 300. no troubles at all.

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    Bill G Bill G's Avatar
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    Quote Originally Posted by kevinedc
    Thanks for the good info. The article was very helpful. Sounds like we should have considered 700x28 instead of 25. It may be that the sweet 16 wheels should be running 700x25. I'll have to check and see what they say.

    That is what I like about the Michelin Pro 2 Race tire, it is a full size tire and measures almost 28mm, just shy, more like a full 700x27C. I like 28mm tires for our team weight as well. The Conti tires measure full size as well, the 25mm tire measures a full 25 to 26mm and the 28mm measures a full 28mm to 29mm depending on the rim. With the sweet 16 the 28mm Conti will be right at a full 28mm in size. Most people run there tandem tires underinflated. The chart I told you about is a pretty good tool and will get you really close to where you need to be. I personaly prefer a full 25mm to 28mm tire myself, some run 23mm but I think they are a little narrow myself for a tandem application and belive it or not they have more roling resistance on a tandem than say a good 28mm tire at the proper pressure for the tandem team weight.

    Good luck,
    Bill G
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    K&M
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    We use Michelin Pro Race 25s most of the time and Conti Ultra-Gatorskin 28s when things get nasty during the rainy season. We weigh in at a little under 300 lbs. and we inflate our tires to about 110 front and 120 rear. In thousands of miles of riding on bad roads we have yet to have a pinch flat.

    We use the Rolf tandem wheels and Rolf recommends against using any tire with these wheels inflated to more than 120psi. Even if the wheels were rated for higher pressure, I can think of no reason why we would want to use higher pressure.

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    Bill G Bill G's Avatar
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    Quote Originally Posted by K&M
    We use Michelin Pro Race 25s most of the time and Conti Ultra-Gatorskin 28s when things get nasty during the rainy season. We weigh in at a little under 300 lbs. and we inflate our tires to about 110 front and 120 rear. In thousands of miles of riding on bad roads we have yet to have a pinch flat.

    We use the Rolf tandem wheels and Rolf recommends against using any tire with these wheels inflated to more than 120psi. Even if the wheels were rated for higher pressure, I can think of no reason why we would want to use higher pressure.

    K&M,

    You should get good performance at the tire pressures you listed your tire pressure matches your team weight, you guys are pretty light. Things change when it comes to tire pressure as the team weight gos up on a tandem. All I can say is the owner of Co-Motion cycles recommended the higher pressure for the Michelin Pro 2 Race tire and our team weight and my Robusta has Rolf wheels. I met Rolf personally at Co-Motions facility when we picked up our tandem. Also, apparently Santana recommended the higher pressure for the tandem tire as well for the weight of kevinedc team ( the original poster of this topic ).

    It has a lot to do with team weight, according to the chart I recommended above a team that weighs 300lbs with a 28mm tire should run 115psi to 120psi which is were your team weight is at, but with the same tire with a team of 350lbs you should run 130psi to 135psi . I have used this chart for quite a while and find it very accurate for tire pressure and team weight ratios.

    Take Care,
    Bill G
    Last edited by Bill G; 09-05-06 at 04:27 PM.
    Co-Motion Custom Primera Tandem (AKA The Marrage Counselor)
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    So far the answers have been about Road tyres But I am an offroader. I use Panaracer Fire XC's on all my MTB's as it suits my terrain. On the Solo I use 1.8's and run them at 50PSi for my meagre 150lbs. This will stop pinch flats and they roll pretty well but still give grip. I occasionally use the 2.1's and use the same pressure.
    Now on the Tandem- a lot of teams use 2.3 tyres or larger. I still use the Fire XC 2.1's and run them at 60psi- which puts them at the top of the pressure rating for this tyre. Still gives grip and due to the construction of the Fire XC, we do not get pinch flats. That is for our 400lbs all up weight on the Tandem. I did at one point use IRC Mythos but got pinch flats at 60psi, although the grip was good. Had to go to 75PSI to stop them on this tyre, and at that pressure, we were losing grip.

    Like a several of the Road tandem teams- I have found that you do not have to go wide- just because it is a tandem. Tyre pressure is all important, and that is dependant on the tyre construction and the weight of the team. Whatever pressure you do use though- Do inspect the tyre frequently for sidewall damage, and every now and then, Say every 6 months- take the tyre off and inspect the interior of the tyre and the tube. Suprising how many marks we have on the tubes from in and out thorns and flints, and how many times we have found the cords of the tyre lifting away from the rubber, just where the flint damage is.
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    Senior Member Retro Grouch's Avatar
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    Quote Originally Posted by Bill G
    We found performance to be better with the Conti 28mm gaterskins inflated to around 125 to 130 PSI and we weigh in at 340lbs to 345lbs as a team plus 30 lbs for the tandem.

    Take Care,
    Bill G
    That's funny. I used to run out tandem tires at 120psi. I lowered them after reading what a lot of other riders had to say. We found the ride to be more comfortable and didn't feel any reduction of performance but those are both just subjective feelings. I honestly don't know how to accurately measure either.

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    Bill G Bill G's Avatar
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    Quote Originally Posted by Retro Grouch
    That's funny. I used to run out tandem tires at 120psi. I lowered them after reading what a lot of other riders had to say. We found the ride to be more comfortable and didn't feel any reduction of performance but those are both just subjective feelings. I honestly don't know how to accurately measure either.

    There is always a trade off in everything we do, most always there is a little more comfort with lower pressures in a tire and most don't or can not tell the diffrence in performance for general all around riding. I ran my 28mm Contis at 120 psi for a long time with no problems to speak of . We did notice a small diffrence in our averages on flat ground long distance riding with the higher pressure, also the tandem performed better in general and had a faster feel to the steering and better cornering performance with the higher pressure as suggested by the chart I recommended above.

    I think it boils down to what works for each teams personal riding style and how they like there tandem to feel. Again to low of pressure is bad for a tandem and I would guess the same for to high of pressure to the extreme side. I personally like the feel and performance of the higher pressure myself and dont care for the mushy or cushy feel of low pressure in tires on my tandem or my road bike for that fact.

    Take Care,
    Bill G
    Last edited by Bill G; 09-05-06 at 10:23 PM.
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    hors category TandemGeek's Avatar
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    My guess on the psi ratings from Rolf/Co-Motion & Shimano/Santana has more to do with preventing rim dings and maintaining that super crisp road feel you get from high pressure racing tires than anything else. Even with 145psi tires we've nailed a few rims riding in pacelines; about $65 a pop for a new Velocity Deep-V rim on at least two occasions (I'm nursing a third rim that's got a marginal rim ding).

    As for "why high psi", beyond the point where you have enough air your tires to give it the right shape and to prevent pinch flats, it's all about personal preferences for road feel. I like to feel every little bump and stone in the road and find it disconcerting going through fast corners on larger diameter or "cushy" tires. Right on wrong, that's my preference. When we encounter really nasty chip seal or roads with lots of expansion joints I'll yield to comfort and drop the psi down to around 115 - 120 to smooth things out.

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    Senior Member zonatandem's Avatar
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    Stoker Kay is quite sensitive to tire pressure and will occasionaly ask: "Did you just air up the tires?"
    We run a Maxxis Detonator front and Maxxis Re-Fuse 25mm tire in the rear at 120 lbs. Team weight just under 240 lbs.

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    Senior Member 72andsunny's Avatar
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    Quote Originally Posted by kevinedc
    Hi,

    We just purchased a Santana Tandem with the Ultra Gatorskins 700x25. The folks at Santana said we should run them at 140 PSI even though the max recommended is 120 psi. I'd sure hate to blow a tire due to too much pressure, but also don't want to pinch flat. Not sure if it makes any difference, but our combined weight is 325lbs. Any thoughts would be appreciated.
    Thanks
    We run 120 PSI in our 700x28 Ultra Gatorskins. I have had 2 sidewall blowouts when they were blown up to around 140 (once from the bikestore and once from a C02 cartridge). A sidewall blowout is quite possibly the loudest thing you will ever hear. I need to switch to better tires.

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    We also run Utra Gatorskins 700X28 on our triple and 700X25 on our tandem. We run them at 120 psi. Should we increase the pressure on the triple?

    Thanks

  17. #17
    hors category TandemGeek's Avatar
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    Quote Originally Posted by cornucopia72
    Should we increase the pressure on the triple?
    Hard to know without total team weight and tire problem history. 120psi may just happen to be a good psi rating for both.

    Rather than pontificating, let me just direct you to Sheldon Brown's general guidelines as they are (as you'd expect) spot-on: http://sheldonbrown.com/tires.html#pressure

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