Does anyone on here use a wider front rim? I ask as I'm quite keen on the Mavic 321 or 521 for the front, which should work well with a 2.25 – 2.4" tyre, but don't think I need anything wider than say a 2.1" on the back, so was thinking Mavic 317/717/719.

Riding a lot of rocky terrain on Dartmoor, on a HT, and find current Cinder 2.1's a little unforgiving, though would probably keep them for the back.

I find that I tend to mash the back wheel up far more than I do the front, which seems only sensible given that's the end with suspension. The 521s and 521s are a lot tougher than the XC rims.

The 521 is way lighter than the 321 for a small increase in cost, and it's welded, rather than pinned. It's still fairly heavy compared to something like a 317 though.

A ZTR Flow is pricer than either a 521 or 317, but it's wider than the 521 and approaching the 317 for weight. I suspect they won't last as well as Mavics – no eyelets.

You riding rigid?

I may be a luddite, but haven't riden rigid off-road for a good few years now… 😆

Tora 318 Solo Air, currently at 100mm. Will be buying new wheels very shortly, so just trying to work out if the more all mountain 321/521 would be beneficial for me with current bike / type of riding, or whether its overkill, and a 317 front and back would be OK…

I know it says max width of 2.3" for the 317 on mavic website, but what do people think works best on that rim, real world riding etc.?

er.. anything smaller than a 2.3 🙄

TBH I wonder about the benefits of massive tyres. I've got some in the shed, and it's like pedalling a tractor. Schwalbe reckon wider tyres + lower pressures equal less rolling resistance, but I'm not sure.

A ZTR Flow is pricer than either a 521 or 317, but it's wider than the 521 and approaching the 317 for weight. I suspect they won't last as well as Mavics – no eyelets.

Never been able to fault Stans for strength. Mavic is old hat relying on old manufacturing processes that just don't cut it anymore on the MTB front; overbuilt and heavy. That's what I reckon anyhoo.

tron – Member
TBH I wonder about the benefits of massive tyres. I've got some in the shed, and it's like pedalling a tractor. Schwalbe reckon wider tyres + lower pressures equal less rolling resistance, but I'm not sure.

You're using heavy, tractor like tyres. EDIT a wider tyre (of the same build) rolls very slightly better at the same pressure, can be run at a lower pressure allowing more grip & thus possibly higher speeds.

OP you can go wider than 2.4 on a 317 etc, but you need to pump them up harder, which may defeat your purpose (not sure what that is though, given you have suspension)

I've got Bonty XR4 tyres (2.35) which are specced for a 28mm rim.

They're super tyres, I use a 519 rim at the front which behaves perfectly. The rear is a very narrow Bonty Race Light TLR and if I run lower pressures the tyre flops about a bit, but pumped up nice & hard it works fine.

if anything, wider/stronger rim at the back where most of your weight is, and where your suspension isn't (?).

even more so if you want to use a bigger tyre at the front; your front wheel will not have a hard life.

big tyres + suspension = easy life for wheels*

(*assuming you put in a few less psi's – there's not much point using big tyres if you don't)

although there is a certain logic to using a wider rim if you want to use a bigger tyre…

You're using heavy, tractor like tyres.

Of course, the solution is to buy light tractor tyres with fragile beads from Schwalbe for £50 a pop 😆

Yes, that's why the pro peleton is adopting balloon tyres and running them at 20psi 😉
erm. I think the lower pressure/low rolling resistance thing only works above a certain bump threshold. i.e. if it's constant large rocks there's some truth to it as a lot of energy is lost getting jiggled around. But for most rides, we're only riding over properly rough ground a tiny percentage of the time so there's a balance to be found.

I wouldn't personally worry about matching a tyre to a rim. I would choose a rim which seems suited to your riding and then choose a tyre which suits your riding. If you don't tend to dent and ding rims, then I don't really see why you need to change unless you really want a proper wide tyre (i.e. above a real 2.3).

I've run High Roller 2.5" tyres on my Mavic 717 without incident for downhill days.
On my next bike I'm looking into Stans Alpine or Crest rims.

TBH I wonder about the benefits of massive tyres. I've got some in the shed, and it's like pedalling a tractor. Schwalbe reckon wider tyres + lower pressures equal less rolling resistance, but I'm not sure.

schwalbe are full of shit – take your huge low pressure shitty schwalbe tyres to a pump track and see for yourself.

Pump tracks are pretty different to normal trails in terms of requirements of a tyre.

The logic behind the lower pressure argument is that every time you go over a bump with hard tyres, some of your forward momentum is redirected upwards and lost. Lower pressures allow the tyres to deform over small bumps meaning less forward momentum is redirected and lost.

If I remember right, the wider tyre argument is to do with the length of the contact patch and how it flattens – on a wider tyre, the flat contact patch is shorter meaning the tyre has less 'leverage' to overcome for the tyre to roll.

I understand the argument, I'm just not sure how it stands up in the real world on the trails I ride. It feels to me like the sweetspot isn't up at 2.4".

OK, thanks for comments, think I may just go with a pair of 317's, since if I don't go over say 2.3" (though I know some here do run wider), I'll be saving myself about 125g per wheel over a 321, and a little less over a 521, and they should be able to handle my 75kg even over the boulders of Dartmoor.

Have to get something as I'm moving to… DISCS!!! 😯 , well I did say I was a luddite 😀

If I remember right, the wider tyre argument is to do with the length of the contact patch and how it flattens – on a wider tyre, the flat contact patch is shorter meaning the tyre has less 'leverage' to overcome for the tyre to roll.

Kind of – the curvature of the tyre that makes up the contact patch is less, meaning less effort to deform it.

Kind of – the curvature of the tyre that makes up the contact patch is less, meaning less effort to deform it.

I probably didn't explain it very well but that it what I meant – a wider tyre is more 'round' under load 😉

I was thinking something similar… I run a 2.35 Blue Groove up front on a 717 rim (PSI I dunno, maybe 30?), but the tyre rolls around a fair bit under cornering – although it's never come off the rim.

I was planning on rebuilding that wheel with a Crest or something wider (but still lightweight) to give the tyre a squarer profile and hopefully reduce the rolling around. I haven't done it yet because I'm unsure about tubeless and I've heard how difficult it can be to get tyres on and off the Crest.

cynic-al – Member
Pump tracks are pretty different to normal trails in terms of requirements of a tyre.

the earth is just one big pump track (omitting the wet bits) – noob!!

🙄

take your huge low pressure shitty schwalbe tyres to a pump track and see for yourself.

I'd rather take a track pump to my low pressure tyres than take my low pressure tyres to a pump track.