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The Tandem tire wear thread got me wondering about tire size. I'm still new to the double-bike thing so excuse me if this sounds like a dumb question.
Our "second hand-but like new" Trek T2000 came with 700 X 28 Conti Ultra 3000's on Bontrager Racelite Tandem wheels. I'm thinking about putting on the Ultra Gatorskins. Everyone says they're pretty tough tires but I figure they probably sacrifice some small measure of performance for the sake of durability. So my question is will a 700 X 25 or possibly even 700 X 23 fit on my wheels and maybe give back some part of that lost performance?
The Mavic Ksyriums on the single bike measure slightly wider than the Bontragers on the outside of the rim. I didn't bother taking a tire off to measure the inside knowing that the experts here will know the answer off the tops of their heads.
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I'm one of those people who likes to go really light and will sacrifice comfort for performance, although I don't consider our current setup uncomfortable at all. We're using 700x23 tires inflated to 120 lbs. Currently we're running WTB Caminos because I was able to get a set off eBay. I think you get used to seeing a certain tire size, so anything else looks wierd. I'm used to looking at 20mm-wide tires on my track bike and on my winter bike (carbon fork with a fender doesn't leave room for a 23) and 23mm tires on my carbon fiber Trek, so putting anything bigger on the tandem would look like balloon tires.
But then, we don't do any loaded touring - the tandem is always ridden with the absolute minimum of weight - no racks, the fenders come off with less than 40% chance of rain, it's only got bosses for two bottles.
No problems over several years of riding, a lot of it on really rough country roads in northwest Washington. The tandem carries around 320 lbs, and it rolls on a 16-spoke Campag Shamal on the front, and a 36-spoke Mavic CXP14 laced to a Campag Record 8-spd hub on the back, 55-46-36 chainrings and 12-26 cogs and a Campag Record derailleur with short cage. The bike has over 6,000 km with this setup and I'm not hearing any funny noises yet.
I've known people who go even further for performance, like using tubulars on their tandem. I'm beginning to think that this whole idea of making "tandem-strength" components is the manufacturers trying to get you to spend more money.
- Luis
The tandem carries around 320 lbs, and it rolls on a 16-spoke Campag Shamal on the front, and a 36-spoke Mavic CXP14 laced to a Campag Record 8-spd hub on the back, 55-46-36 chainrings and 12-26 cogs and a Campag Record derailleur with short cage.
The bike has over 6,000 km with this setup and I'm not hearing any funny noises yet.
Luis
Luis,
Thanks for your reply. Can you dumb it up a bit for a rookie tantem team? The simple question is; Can we put 700 x 25, or 700 x 23 tires, on wheels that came O.E. with 700 x 28 and expect them to stay on the wheels throughout all conditions regardless of ride comfort? And will they go on and off just as easily if we have to change a flat.
Secondary question is ;will the 25's or 23's be much more effecient than the 28's?
No idea what Bontrager Racelite tandem wheels look like, but if they're narrower than Ksyriums, I see no reason not to try. I regularly run 23's on my Ksyrium rear wheel (can't afford the matching front!). As it says in Sutherland's bike mechanic's guide, "One measurement is worth a thousand expert opinions."
Same thing goes for tire efficiency. I would think the 23's would be more "efficient" than 28's, but maybe there are different dynamics working on a tandem as opposed to a single that I don't know about? For now, I would use the 23's until someone can show me that 25's or 28's are more efficient. After all, we ran 21's on singles until they figured out that 23's were more "efficient," or at least gave a better ride without significant loss of efficiency.
- L.
In general,.... If Internal rim width is 15mm you can safely use from 23's to 32's; if 17mm, from 25's to 35's ( I suspect than is what you have); is 19mm, 28 to 35. Hope this helps.
Can we put 700 x 25, or 700 x 23 tires, on wheels that came O.E. with 700 x 28 and expect them to stay on the wheels throughout all conditions regardless of ride comfort?
I would say that, as a rule of thumb, you should be able to go up or down one size from an O.E.M. spec' tire size without getting into marginal size issues. However, to be sure, it's best to measure the inside diameter of a rim and, as others have noted, the assumption for the Bontragers Race Lite Tandem is that they are somewhere around 15mm - 17mm wide, giving them a "safe range" of 23mm to 28mm, 32mm if they are 17mm wide.
The other wild card would be initial tire/rim fit. Not all tires fit all rims as well as they should so, if upon initial installation the tire goes on to a given rim a bit too easy, a wary eye should be kept on that tire... particularly if it's a foldable model vs a wire bead tire.
Gatorskins don't seem to fall into this misfit category, and neither do the Bontrager rims. Thus, your proposed change to 700x25 Gatorskins for your Bontrager Race Lite Tandem wheels would be a good match-up.
And will they go on and off just as easily if we have to change a flat?
They should... again, noting that some tires fit rims better out of the box than some others and some foldables "stretch" more than others after they have been mounted for a while. My foldable Vredestein's (23mm or 25mm) go on tight out of the box, but become very easy to pull off after the first couple hundred miles.
Secondary question is ;will the 25's or 23's be much more effecient than the 28's?
Depends on your team weight, your road conditions, and PSI. If you have less than perfect road conditions, 28's might prove to be more efficient than rock-hard 23's. If you are a lightweight team with very smooth roads, dumping the 320g 28's for 230g foldable Gatorskins could give you a more responsive feeling bike.
As another that's new to tandeming this spring, let me share my observations. Our Burley had only a couple of hundred miles on it when we purchased it from the LBS, but his teenage daughters had been riding it and they had 700x23's on it to try to get it a little more "racy". After four rides, I swapped out the 23's for a set of 25's I had on another bike, and am really glad I did so. I didn't really notice any performance differences, but the bike felt much more stable under us, and given our lack of tandem experience, that helped our confidence level a bunch.
You may find yourself in a different situation from us, but we agreed that the larger tires were better for us at this point.
For now, I would use the 23's until someone can show me that 25's or 28's are more efficient. - L.
Actually, Michelin has done some studies where they claim that 25s are more efficient than 23s. I'm not sure about all the technical stuff, but I think I recall that part of the reason is that a 25 will squish down less than a 23, thereby actually having less surface area touching the road (so less rolling resistance). I've just switched to 25s (from 23s) on my single and really like the difference--no slower, and much more comfortable.
As for the original post--something else to consider is that different companies will have different width tires. For example, a conti 25 is closer to a true 23 while a Michelin may come in closer to a 27 (depending on the rim).
Trusted local tandem mechanic says pretty much the same. I could put 25's on but not gain much if anything. I ordered a set of Gatorskins in 700 x 28 and will also pick up a foldable Conti 2000's in the same size to carry as a spare on unsupported rides.
it rolls on a 16-spoke Campag Shamal on the front
- Luis
Am I the only one who thinks this a bit loony? I am guessing your stoker has know idea that wheel is designed for single bike time trial applications?
I am new to this forum, this post was interesting, now for a little history. My wife and I have ridden a road tandem for quite a long time together now. We have had four tandems a KHS, Cannondale, Trek and the Co-Motion supremo we ride now. We are in the process of having our fifth tandem frame set built, it will be a new custom Co-Motion Robusta.
The Bontranger tandem specific race lite wheel is designed for tandem use and it is not for single bike use like the regular race lite wheelset. The Tandem specific race lite likes a 25mm to 28mm wide tire due to it being around 19mm wide from braking surface on one side to braking surface on the opposite side. The 28mm wide tire will actually have less roling resistance at 120 PSI and corner better, support more weight, ware better and give a much better ride. A person has to pump up a 25mm tire to around 145 PSI to get about the same rolling resistance as a 28mm at 120 PSI on a tandem with a harsher ride. A normal 25mm tire in my opinion can be a little narrow on a road tandem application in my opinion. The Continental Ultra Gater skin is a great tandem tire and we have had no tire failers in three years now with them, they are bar none the best tandem tire on the market.
I think the choice of a 28mm gater skin was a great choice.
Good luck,:)
Bill G
I think the choice of a 28mm gater skin was a great choice.
Good luck,:)
Bill G
It's easy when you get great input and advice.
Trusted local tandem mechanic says pretty much the same. I could put 25's on but not gain much if anything. I ordered a set of Gatorskins in 700 x 28 and will also pick up a foldable Conti 2000's in the same size to carry as a spare on unsupported rides.
Good move. Remember, Cap'n, your responsible for somebody else on that bike (your stoker!). We ride Gatorskin 28's on our tandem. Our team weight is right at 320 lbs. Tough tires. Tried a set of Specialized Armadillo 28's last year, was really dissappointed in the sort of lifeless performance. Gatorskins are a good compromise between performance and durability.
BTW, the Armadillos were bulletproof. But then again, we've only flatted twice on the Conti's in better than 8K miles of cycling (three sets of tires). We wear 'em out before we cut 'em.
I think the choice of a 28mm gater skin was a great choice.
Good luck,:)
Bill G
They rode great for 37 miles Saturday. The rear pinch-flatted Sunday about 20 miles out. I chalked it up to old tube in new tire and put a new tube in very carefully. Rode another 46 miles w/ no problem. Monday AM it flatted again twice before we got out of the parking lot. We put another tire on to save the day and did 52 miles trouble-free. I notice there's a small rough spot where it looks like the wire bead has delaminated from the casing and figure that's the problem, not sure what caused it, will investigate further.
The rear pinch-flatted Sunday about 20 miles out. I chalked it up to old tube in new tire
How can an old tube in a new tire cause a pinch flat? A pinch flat is normally due to a (relatively) under-inflated tire striking a pothole or some other object very hard, so that the tube folds and is smashed against the edge of the rim. (Ouch!)
Monday AM it flatted again twice before we got out of the parking lot.
Sounds as if the culprit (piece of glass? staple? nail?) was not removed from the tire casing before you repaired it the first time. Did you reference the leak's position against the tire, and find where it was compromised? Was the second flat in same location (referenced to the tire) as the first flat? I always locate the casing hole, or the offending object, as part of every flat repair.
-Greg, who has had well over a dozen flats so far in 2006, most due to glass!
How can an old tube in a new tire cause a pinch flat? A pinch flat is normally due to a (relatively) under-inflated tire striking a pothole or some other object very hard, so that the tube folds and is smashed against the edge of the rim. (Ouch!)
Sounds as if the culprit (piece of glass? staple? nail?) was not removed from the tire casing before you repaired it the first time. Did you reference the leak's position against the tire, and find where it was compromised? Was the second flat in same location (referenced to the tire) as the first flat? I always locate the casing hole, or the offending object, as part of every flat repair.
-Greg, who has had well over a dozen flats so far in 2006, most due to glass!
Tandem riders more experienced than me called it a "pinch flat", said I need to put talcum powder on the tube before I install it. 2nd and 3rd appear to be caused by delamination between the rubber casing and wire bead. I'll show it to the mechanic before I claim it defective or caused by "operator error" from improper installation. I had to use a tire tool to get both new tires on. I've done it before and never damaged one.
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