Originally Posted by
jefnvk
So the bike I'm currently prepping came with 40mm Schwalbe Marathon. They feel decent, definitely plush, just wondering if there is a drawback to going big. Most of my bikes have/have had 32-35mm tires, which I enjoy, but these things look monstrous and too far in the fat direction.
First, consider what the difference between 40mm, 37mm and 35mm tires are. 3, 2 and 5mm. 5mm isn't even a quarter of an inch. 3mm is just shy of 1/8" and 2mm is just shy of 1/16". Are those really that large a difference? Going from a 40mm to a 37mm is a trivial volume difference. Going from 40mm to 35mm is still trivial.
Consider the difference at the contact patch which is the only place it really matters. A 3mm change in height is like adding a nickel under your tire. Is it really that radical a change?
Originally Posted by
jefnvk
Besides weight, is there any practicable drawback to a bigger tire? I've also got a new set of Conti Top Contacts in a 37 (which come out far closer to my 35 Clement USH than these 40 Marathons) I'm considering tossing on, but if there is no drawback I'll probably just run these into thr ground
I'm not sure the weight difference is going to be all that great either. Frankly, I'd be more concerned about the crappy performance of the Continentals. I've had far too many problems with Continentals...including getting stranded at a campground in Atlanta, Texas after the 4th blowout in the first 26 miles of a tour (see Twisting Down the Alley) below. A Bell tire from Helmart is better...and I've had to use one to replace yet another Continental failure.
Originally Posted by
Tourist in MSN
What inner width do you have on your rims. Some rim manufacturers make wild claims like one of their rims will work fantastic on any tire from 23 to 57mm wide. But I think the chart on teh bottom of this page is the best chart out there.
Tire Sizing Systems
Sheldon Brown's chart is very conservative. In my opinion, too conservative.
Originally Posted by
Tourist in MSN
I unfortunately have a set of rims that the manufacturer claimed would be good for up to 57 mm. And the dealer said they were the best rims you could buy for an expedition bike so I bought them thinking that the dealer had a clue. Unfortunately, the dealer had no clue, the rims are 19 mm wide (inner width) and the bike handles terribly if I try to run the 57 mm tires at low pressure because the rim is too narrow. The chart for 19 mm width says my tire should be no more than 44 mm wide.
How does the bike handle and what pressures are you using? I regularly run 2.2" mountain bike tires on 17mm rims at 40 to 45psi on the rear (with and without rear suspension) with 50 to 55 psi on the front (with and without a suspension fork) and have never had any kind of handling issues either on- or off-road. I know that current fashion is to run tires with stupidly low pressures but I've never found flat tires to give a desirable ride and I like my rims. I corner hard on both pavement and off-road and never found that wide a tire on that narrow a rim with that pressure to have "handling" problems.
That's also the pressure I use for bikepacking.