29+ tyres on 'narrow' rims

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This topic has 18 replies, 11 voices, and was last updated 7 years ago by molgrips.

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29+ tyres on 'narrow' rims
cp
Full Member

Planning a bit of an experiment with a 29+ on the front of the scandal 29er.

Currently have a 2.3 and a 2.4 tyre on 19mm internal width rims (WTB Frequency i19) and they seem OK. I appreciate the ‘ideal’ rim would be wider for the much larger tyre volume but is anyone running 29×3 tyres on 19mm or similar width rims? Any fundamental issues?

Posted 7 years ago

jimfrandisco
Free Member

will be watching this with interest. From what i’ve heard fat tyres on narrow rims defeat the purpose as you have to use high pressure to ensure they don’t squim off the rim.
Assume you’re just talking about the front – my scandal can only just fit a 2.2″ in the rear?

Posted 7 years ago

MostlyBalanced
Free Member

As above. You’d have to pump it up so hard to stop it squirming that all you’d notice would be a heavier tyre and wheel.
If you’re only going to change one thing change the rim for a wider one and stick with the 2.4. I changed to 48mm rims and now run 15 PSI in 2.4s with no squirming and a big increase in comfort and grip. I run 3.0s in the summer when mud clearance isn’t such an issue.
Look around and do you see any other vehicles with tyres pinched in to such dramatically narrower rims? Cars don’t, motorbikes don’t, even wheelbarrows don’t.

Posted 7 years ago

Fresh Goods Friday 700 - The censored edition

Cheezpleez
Full Member

I’ve got a Knard on a Crest on the front of my Swift. It’s not perfect (I’m running it at 15psi compared to the 10-11psi I run on my Stooge with a Dually) but it does most of what I want it to. I use the Swift mainly for long days and loaded-up trips.

I’m planning to switch to a wide rim at some point on the Swift but it’s good enough that I’ve not bothered so far.

Posted 7 years ago

cp
Full Member

Interesting feedback, thanks folks. I did wonder about squirm. My 2.3s and 2.4’s have a reasonably fine operating window in pressure, but I do like my tyres on the firm side anyway.

Definitely front only, rear is 2.4 max on a 19m rim in the scandal. Would be for summer use – to take a little sting out of the rigid front end.

Might get a tyre to give it a try – I’ve got a spare front hub loitering round so can always build it into a wider rim if need be.

Posted 7 years ago

cynic-al
Free Member

From what i’ve heard fat tyres on narrow rims defeat the purpose as you have to use high pressure to ensure they don’t squim off the rim.

This. You will get some of the benefits but not all…

Posted 7 years ago

faustus
Full Member

I really wouldn’t bother with 19mm rims, 25mm might be bare minimum perhaps but still a compromise. I’m going to try it on the front of my (rigid) Scandal on a 30mm rim which should be OK

EDIT – Easton arc 30 rims are £40 on CRC at the mo if you have a hub lying around…

Posted 7 years ago

molgrips
Free Member

I’ve got something like 27mm internal on mine, I might buy a plus tyre then for a laugh, tide me over until I rebuild the wheel 🙂

Posted 7 years ago

cp
Full Member

EDIT – Easton arc 30 rims are £40 on CRC at the mo if you have a hub lying around…

only 27 width in 29er sadly. I’m a little loath to spunk 80 quid at a 40+ rim, but may if it makes a difference.

Posted 7 years ago

cp
Full Member

Oh hello, Easton Arc Plus are reduced to £50… interesting!! Might go all out on a 45mm width then 🙂

Posted 7 years ago

Bimbler
Free Member

I’d say don’t do it. I put a set of Big Apple 2.5s on my 19mm rims and it felt super squirmy, even when pumped up to 40 psi+

Posted 7 years ago

cp
Full Member

Went with 40mm wide arc plus and WTB Ranger TCS light fast rolling, with £10 off clearance all came to 85 quid. Nice little spring project there 🙂

Posted 7 years ago

faustus
Full Member

Nice one! Thinking of doing similar – the custom wheel build for a front comes at £109 which ain’t bad…

Posted 7 years ago

goss
Free Member

I went down to i19mm for a cheap hardtail build with 2.2 tyres and that felt squirmy compared to my other bikes with i29mm rims with 2.4 – I wouldn’t dare to put a knard or chronicle on a Crest or Arch rim, maybe only for fun.

Last week I set my spare wheel, Halo Vapour 35 (i30mm), up with a spare Conti Cyclocross 35mm tyre just for fun and to please my curiosity. The tyre ended up measuring 37mm 😕 😯

Posted 7 years ago

ajantom
Full Member

I’ve run a Knard on a Pacenti DL31 rim – about 26mm internal. Was fine, but had to run it a bit harder than I would with the 50mm wide Rabbit Hole rims.
I suspect that with a 19mm internal it might be a bit squirmy.

BTW, if you’re anywhere near Exeter/Honiton I have a couple of spare Knards – they’re fine tread wise and go up with tubes, but have a couple of small holes so won’t run tubeless. You’d be more than welcome to borrow one to experiment with.

Posted 7 years ago

molgrips
Free Member

Would you put 2.35s on a 40mm rim?

Posted 7 years ago

ajantom
Full Member

Would you put 2.35s on a 40mm rim

I’ve put 2.4 Chunky Monkeys on a 50mm rim. Makes them very wide and a bit square. They rode very well.

Posted 7 years ago

birdage
Full Member

2.4 Ardent on a 40mm rim here. Also tried a 2.35 Hans D. Works for me. Got the rim from Ridewell in Italy, about £30 delivered. Recommended.

Posted 7 years ago

molgrips
Free Member

Wondering if I should build a pair of wider rims for general MTB usage, and use the ones I have for narrower tyres.

Although what I probably need is a pair for narrow tyres, a pair for wide tyres then another front wheel for the 50mm rim.

Posted 7 years ago