challange one tubular tyres are they round

[bm0p700f]

I have just fitted a pair of challange one 29er tubs to my new race bike and I am a bit dissapointed. They do not appear to be very round. 8mm difference in the height at its worst point. Does not seem normal to me along with a wobble at the low point. The Geax Saguaro's I have used before and will use again when more turn up were round and straight. Anyone had any issue with challange MTB tubs, is it worth getting the warranty replacement or will the new ones be just the same. If it were one it could be bad luck but both of them being the same makes me think they are not made properly.

As the race is on sunday I have no choice but to ride them (the distributor says that will not be a problem), I know I will be able to feel this up and down motionof the tyre on the fire road sections

[the_marsbar]

Hmm. I had this problem with a pair of cross tubulars (also Challenge). Not as much though, but still annoying. I believe it was around the stem (and yes, I tried my best to get the tire pressed into the rim cavity).

[LeDuke]

Yes. Poor quality control. One of mine is "ok", the other is horrendous.

Also, they are VERY tricky, pressure wise.


My Tufo XC4s are a much better tire. Not even close.


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[bm0p700f]

Well 28 psi in the first race with them today went O.K but a silly token WW seat post clamp let me down and the post slipped down. when the Geax Saguro's arrive these will be coming off and will be going back to the distributor. I know now to avoid there other tubs as well. I hope the strada clincher is better.

[njee20]

May I suggest a bit of training, rather than WW seat clamps and expensive tubs!?

[the_marsbar]

njee20, I suppose you know nothing about bm0p700f's level of fitness. What's the problem if he wants to ride lightweight stuff (don't we all...?).

[njee20]

I happened to have the race results from yesterday open in another tab. So yes, I know about his fitness levels thanks! It would have been a meaningless comment otherwise.

Lightweight stuff is one thing, no substitute for training though is it? My comment was tongue in cheek, but I have to chuckle at the outrage that the OP will feel the undulations in his tubs on the fire roads...

[the_marsbar]

Really? It was quite noticeable with the Challenge cross tubulars that I used. Even on fire roads...

There were no tongue-in-cheek-indicator (a smiley). But of course it's not a substitute for training

[bm0p700f]

My level of fittness is not that great as the leaders but my main problem is not fittness but lack of off road riding I just can't seem to keep the same pace over the rough stuff as others. That is down to bike skills and how you handle the terrain. I am not very good at it. Still without the sinking seatpost (solved with some carbon paste) and the dodgey tubs I would have done a bit better than I did, I felt I slowed alot on the last lap as I got tried of standing up (I stopped a couple of times to raise the post loosing more time).

[TheKaiser]

To the OP, not sure where on the tire the high point was, but since another poster mentioned an issue at the valve, I just wanted to mention this:

Some manufacturers have a much more prominent disc or cone of material joining the tire/tube to the valve, which leads to what is effectively a reduction in the ID of the tire at that spot. Also, there is inconsistency between brands of rims in the diameter of the valve hole in the outer wall of the rim (that the tire seats on). Some make the hole a bit larger than the one on the spoke side of the rim, others make it similarly sized. Anyway, you can probably see where this is going...if you have a tire with a big cone of material supporting the valve, and a rim with a particularly small hole for the valve, there is nowhere for it to give or accommodate, and you are left with a lump. If you have a rim that is making it tough to get a large number of your favored tires to run true at the valve, you can enlarge the hole, and/or bevel it, to make room for the valve base material to countersink into the rim a bit.

Obviously if the hop is elsewhere on the tire then this doesn't apply at all.

[bm0p700f]

Yep the hop or should I say the dip is opposite the valve so there is nothing I can do. Did alot better in todays race though 10th on lumpy tyres, not too shabby, looks like the training since the last race is paying off.
Does anyone here use dugast MTB tubulars, I am still waiting for the Geax ones to arrive so am I am looking at other options.

[jooo]

Tufo or Schwalbe RaRa HT are good options.