EddNog

This is actually a gravel bike question, but I didn't see any section for gravel bikes, so I went with the hybrid bikes department...

I tried the search and got no result, so I am asking here--has anyone tried running staggered WHEEL (not just tire) sizes on their gravel whip? How did it work out?

I've a Lauf Grit on its way, to upgrade my Renegade (2016 Exile frame, so replacing the stock rigid chro-moly fork), and I've been toying with the idea of running a reverse mullet, 27.5x2.X party in the front and business-class 700c in the back (somewhere in the 35-42mm range). One such combination that seems reasonable is the new Schwalbe G-One Bite tubeless, with the 27.5x2.1 in front and the 700x38 out back. Trying to figure out if that would work better than just keeping my current, dual 700x42 WTB Resolute setup.

Yes, I do realize that the 27.5x2.1 tire is not quite as large in diameter as 700x38, but the Lauf Grit is slightly longer, axle to crown, than my stock fork, even after factoring sag.

-Ed

pjthomas

If you mean running different width tires, 700x32C and 700x35C, this is done all the time. If you want different diameter wheels the limitation is the braking. If you have rim brakes, then you can't. With disk brakes you can IF you have a high enough bottom bracket to clean the ground with smaller diameter wheels. Some bike frames are meant to accept different size disk wheels; 29er and 27.5.

jimmie65

https://www.bikeforums.net/cyclocros...-recreational/

EddNog

Thanks; correct, I mean wheel & tire combination. I, and many MTB riders, have run staggered tire sizes for ages now. I am more specifically wondering about staggered wheel sizes.

You wouldn't have known this, but I don't run rim brakes or tubes on any of my bikes, so yeah, the brake issue is a non-issue.

For clarity, the frame is a Jamis Renegade frame, the fork is being upgraded to a Lauf Grit. I am currently running a pair of WTB Resolutes in 700x42, but I am pondering running 27.5x2.X in the front once I get the Grit installed.

-Ed

EddNog

Thanks; I totally didn't see that section. Would a moderator be able to kindly move this thread into that area for me, given my complete blindness?

-Ed

pjthomas

It should work but I'd stick with the 42 Resolutes.

EddNog

Fair enough; I actually love my Resolutes so far. Better than even the Horizons I previously ran—the FEEL is that the compound is so much softer and the carcass so much thinner/more supple that, despite the knobby tread, the Resolutes still roll faster than the (admittedly much more durable) Horizon/Byway sisters. This is purely how I perceive by feel; I haven’t done real roll-down comparison testing to be sure.

-Ed

Skipjacks

I've never run different wheel sizes. But I've run different tread patterns. Grippy on the back, smooth on the front.

It didn't last though because my OCD kicked in and it drove me crazy.

Rode nice though.

Kontact 

What would be the benefit on a hybrid?

EddNog

If it’s ridden on unpaved trails and loose surfaces frequently, it helps to have higher front than rear grip (same reason trail riders equip MTBs this way). And the same reason I am considering equipping my gravel bike this way.

-Ed

Kontact 

Different wheel sizes on MTBs made a little bit of sense with technical singletrack riding on bikes built for it, but I can't imagine how having your front wheel 4mm larger than your rear helps you roll down a gravel path.

EddNog

Sorry, I don't follow what you're saying, because a 27.5x2.1" tire is smaller in outer diameter than anything bigger than a 700x35 out back (which is roughly the same outer diameter as 27.5x2.1"), not larger. If I run a 27.5x2.25" front tire (although Lauf only rates the Grit up to 2.1"), I can get similar outer diameter by running a 700x38 out back. If I keep my current 700x42 tire out back, the fork is not wide enough to fit any 650b tire big enough to match the 700x42 Resolute in outer diameter.

The only thing that would change is contact patch size (due to lower air pressure, the contact patch will be larger in area) and shape. The larger contact patch would help with traction on loose surfaces. The lower air pressure should also help with allowing the tire to conform to uneven surfaces. Ideally, I'd run 27.5x2.X front and rear, but my frame won't fit anything nearly that big out back (largest I think I can go might be 700x45 and 650x47 just barely clears, so definitely nothing bigger than 650x50 out back).

-Ed

pjthomas

I just bought a set of folding Panaracer Comets. Cheaper but similar tire. I haven't had a lot of time on them, winter here, but they do roll very nice, even on pavement. New tires always feel sluggish until they are worn, just like sneakers. These didn't and I think it's the small blocks, just like the Resolutes.

A lot of hybrid/commuter tires have a solid (or near solid) center strip and that thick strip has to deform when rolling. The blocks do not deform, rather the thinner casing around the blocks deforms around the blocks. This makes for lower rolling resistance.

Kontact 

Sorry, I misread 27.5 as 27.

As a workaround for a frame that won't take the width tires you want, being too narrow in back, I guess it makes sense if you already have the wheels.

But it sounds like a workaround for a bike that isn't what you really ideally would ride, if you prefer bigger tires than what fits front and rear.

EddNog

So there's been a bit of a change of plans because of an unexpected issue (mostly from my own lack of experience).

The stock, rigid steel fork that comes with a 48cm 2016 Jamis Renegade Exile is 385mm long from axle to crown and has a 57mm offset. The Lauf Grit is a significantly longer 409mm (factoring sag) and also significantly slower 45mm offset. The result of installing the fork while running the same size wheel & tire front and rear results in...shall I say...extremely undesirable handling feel (due to a massive increase in trail combined with slackening of head angle).

After spending over 5 hours doing a LOT of complex math analysis, I've come to the conclusion (after factoring for sag/15% drop at correct inflation level plus change in head angle due to staggered tire sizes) that by running a tire in the size range of 26x1.9 or so in the front will rectify the handling issue introduced by the significantly different length and offset fork. To test my theory, I mounted a 700x32C tire to the front and let a whole lot of air out (it's set up tubeless) to try and simulate the effect, and was able to simulate approximately a 26x2.1 size tire at full inflation, and rode it around for a bit, and my theory seems to work, as the bike's handling is fine again (besides overly squishy tire).

I am having a 26" wheel with 15x100 hub laced up by my LBS now, and have an appropriate size tire on order. Once everything is set up and I give it a proper test ride to confirm that everything is working as I expect (and I am fairly confident that what I expect is finally right), I will post up pics of the completed beast! Right now, I am planning to run a WTB Riddler 45C out back and a Schwalbe Thunder Burt 26x2.1 up front, with the front tire inflated to ~15% sag under load and the rear inflation level to be tuned depending on how the bike handles.

-Ed

EddNog

And we're done. I was inspired by the gold accents in my bar tape and the coincidental gold accents on the 26" rim I chose for this build (WTB KOM i23 26"), so while I was at it, I used black and gold vinyl tape to accentuate the design of the bike and to help create visual harmony between the wheels, the fork and the frame. The results of the wheel & tire matching are as expected, based on my math, and the bike now handles how I want it to again. Here are the as-promised pics:






Front wheel is a WTB KOM i23 26" 32H rim laced to a Shimano SLX 15x100 centerlock disc hub with Sapim CX Ray spokes and brass nipples. Rear wheel is the stock real wheel with Alex ATD470 32H rim, decals removed on the drive side. The tires are Schwalbe Thunder Burt 26x2.1" front and WTB Riddler 700x45C rear, both set up tubeless. TRP Hy/Rd brakes. SRAM Rival 2x11 levers, SRAM Rival 1 Long Cage derailleur and GXP crankset, absoluteBLACK 44T narrow-wide direct mount oval chainring, KMC X11SL-DLC chain, Sugek 11-52 cassette, KS Exaform 861 27.2mm suspension dropper post (hooked up to the left shift lever, detentes removed), Fizik Antares R3 Versus Evo saddle, Supacaz bar tape, Lauf Grit fork.

-Ed

andrei_r

Wow

I want this to be my bike.

ColonelSanders

Wow, your bike looks incredible.

fietsbob

Way Back there was the Ibis Mountain Trials bike 24" rear 26" front..

MisterK

What a strange looking fork