Wide tubular tires on narrow rims

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RichTheRoadie
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by RichTheRoadie

Wide tubular tyres have been around a lot longer than wide tubular rims - you can run 28s on 19mm wide Ambrosio Nemesis without issue, so why should anything else be a problem?

The handling and adhesion on a wider rim should, in theory, be better but there are so many variables (including a decent glue job and a well-made tyre) that I doubt you would genuinely feel a difference (other than perceived benefit) anyway.

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RyanH
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by RyanH

Yes, wide tubulars have been around for a long time but if we take this idea to the extreme where a rim was only a few mm wide, then the tire would most certainly wobble around due to insufficient support. Conversely, I'd think that a tire would behave differently if half of the tire was supported by the rim.

Just to put some numbers to this, a 19mm wide rim has an arc length (contact patch with the tire) of 20.9mm while a 26mm rim would have a contact patch with the tire of approximately 31mm (assuming both rims have a rim bed radius designed for a 28mm tire). So, those that are suggesting there's no difference are saying that a roughly 50% increase in surface area being glued to the rim wouldn't affect the feel of a tire?

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kgt
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by kgt

It would affect the feel so little that practically... it wouldn't.

RyanH
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by RyanH

And I'm guessing you'd suggest that the Vlaanderens I tried mounting on my CCU today but ended up sitting a full 2mm higher than on my other wide rims will handle the same too... Cause not being fully seated in the rim channel isn't a big deal either....

There's no way for this to be tested ceteris paribus. For example, old Boras vs New Boras will handle differently so it's not possible to compare on an equal basis. Presenting confidently that there is no difference strikes me as either daft or ludicrous without being able to say that you tested two wheelsets with narrow and wide tubulars back to back (4 tests).

For example, I had Vlaanderen on the narrow Ksyrium and it was a sloshy mess throwing the bike around. That wasn't as much the case with Enve 3.4 which has a much deeper rim bed. Ksyrium are laterally flexy though compared to the Enve so it's not apples and apples.

RichTheRoadie
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by RichTheRoadie

I had Vlaanderens on CCUs - they were great; and felt no different from my current model HED Stinger 3s. There's no reason for concern if they're fitted properly.

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kgt
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by kgt

Some people can even 'feel' their dead relatives so, I guess, everything is possible...

RyanH
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by RyanH

Well, I can't feel my dead relatives...but my experience today confirmed one of my suspicions.

Last year I had Vittoria Pave 28mm on Reynolds ThirtyTwo and the wheelset became somewhat unstable at speeds above 30 mph. I thought it was a bad glue job so I remounted them, yet the bike was still "darty" above 30 mph. When I put 23mm Contis back on, back to normal, super stable. Today, I had the 25mm Roubaix on the Mavic CCU and the bike was darty at 20+ mph, exactly like how the ThirtyTwos were. The CCU rim bed is definitely a more aggressive shape designed for a 23mm vs the Reynolds, which probably would be okay with a 25 since it appears to be a little more relaxed at the lip.

I'm not sure about others on here, but I do run my tires at low PSI which may contribute to my experiences. I run Roubaix at 65/85 (I'm 70kg) which is a great pressure with Boras or even the 23mm wide Ksyriums.

sungod
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by sungod

fwiw a couple of months ago i reverted to narrow tubs on the front, only just wider than the rim (veloflex sprinter on obermayers)

they are more stable in strong winds (in lanzarote a few days were >40 kph with stronger gusts) the handling improvement was really surprising, far less snatchy as the yaw angle changed, and i'd guess drag is also lower as maximum speed on fast sections of regular routes is consistently a few kph higher - not been any other changes, same weight and position

perhaps the V section rims are particularly ill-suited to wider tyres

Zoro
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by Zoro

I started a new thread in cross about 33mm on 20.5. I know you guys will go nuts over that. These are tubulars, and they are different.

We use the 27/28 Veloflex Vlaanderen on the Easton ~20mm wide rims with no issue for road. They are pumped to 80psi.

For cross, it is different, I expect and this is new territory. For road - no problem at all.

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Wingnut
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by Wingnut

I had some training wheels built up from some NOS Mavic Mach2CD rims, I glued up some 25mm Vittoria's on them and despite the rims being quite narrow the wheels feel fine. I just put two layers of glue on the tyres and two on the rims too. Glue job is solid so I don't get much roll of the tyres when turning or hard leaning over, I've got my tubulars pumped to approximately 85psi each.

My 28mm Vittoria Rubino's on another pair of hp wheels feel too wide though, the Veloflexs in 25mm ran very narrow more like 23mm but they're hp's so not relevant.
"It's not the destination...it's the ride!"

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