Updated post / query:

After riding for a few more weeks using both my 26x2.2" and 29x2.4" bikes on the same trail, I've come to the solid conclusion that the 26x2.2" (Panaracer Fire XC Pro), either the size and/or tread, is not sufficient for the trails. In the soft stuff, they are too squirrely and/or the bike stalls (I can break the rear tire and just spin it). The 29x2.4" (Ardent) traverses with relative ease. Both tires are at 25-30psi (I tried lower and higher psi).

The problem with the 29x2.4" is now I'm concerned about sudden failure, especially on downhills (non-technical, just pick up speed) where I can go 20+mph if I want (shared trail so I usually keep it under 15mph though).

Will 29" inherently be better than 26" - so 29x2.2" will be noticeably better than 26x2.2" (assuming same tread)? Or about the same?


Is my 29x2.4" better than my 26x2.2" because of 29"? 2.4" vs 2.2" Fire vs Ardent tread? All of the above?

If I can get better than 26x2.2" but not as good (but close?) as 29x2.4" with 29x2.2", then I may try to get new tires. If 29x2.2" won't be any better than the 26x2.2", then I'll plan to get a new bike next spring when the sales start).




Original Post:

I just learned about bike rim and tire sizes.

I have a 622-17 rim for my 29er. Current tires are Ardent 29x2.4. Given 17mm, I think the recommended tire size is less than 2" so although the stock tire was 2" I think.

How dangerous is it to have the 2.4" tires on right now. I'm just trail riding, no jumps.

This message has been edited. Last edited by: konata88,

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Many answers at cycling forums.

quote:

I just learned about bike rim and tire sizes.

I have a 622-17 rim for my 29er. Current tires are Ardent 29x2.4.

I sold my bicycle not long after getting my driver's license, so things have probably changed a little. Bear with me.

I don't understand the first part. Does it represent the diameter/width respectively in millimeters? If so, they don't add up. 622mm is ~24.5 inches, and 17mm is implausibly narrow.

If I read the rest correctly, you are running a wider tire on a rim made for the lesser width. The wider tire inevitably adds weight, if only a few ounces. Putting this weight on the stationary frame is insignificant. Putting it on the rotating mass of a wheel (think of it like a flywheel) increases pedaling effort. I can't imagine there would be a safety problem; you aren't going that fast.

I would think that a wider tire than one designed for a specific rim would put excess stress and wear on the rubber where it meets the rim. I don't know that I'd call it "unsafe", as you're not going 70 down a freeway in heavy traffic, but I would imagine that the tire would fail prematurely.

I did some reading on fit and there are suggestions that 622-17 can fit up to about 2.0" tires. But I don't know how to interpret "suggested" comments. I haven't found any page that explicitly indicates unsafe although I get the feeling that it's what they are trying to indicate. But I'm not jumping or riding aggressively; I'm not having to lean into corners to ride the side lugs. Speed is generally less than 15mph.

So a popular outdoor shop installed unsafe 2.4" tires onto my rims?

Okay assuming that this is unsafe:
1. I should install 2.0" tires. But this may make riding on my trails challenging - insufficient traction for going uphill on loose hardpack / soil; challenging to brake on same; less float on sand (lake side).

2. Get new rims - expensive - probably cost more than the bike is really worth. Not palatable.

3. Get a new (used) bike w/ desired rim size - expensive but perhaps the best path.

#1 is cheapest but may not lend itself to my riding locations, #2 seems out, #3 is financially unpalatable.

#1 may work if I can find an aggressive tread in 622-17 but everything good seems to be 2.2" or 2.4" and wider....

622 is the diameter, 17(mm) is the interior width of the rim.

To answer the original question...Well, it depends.

You indicate Ardent 29x2.4 Tires - Those are tubeless ready...Are you running them tubeless, or tubed on a clincher rim? For the record, there are also both crotched/hooked wall rims and straight wall/hookless clincher rims. What type rims do you have? Make/Model of the rims if you're not sure of the design?

What tire pressure(s) do you run?

You indicate trail riding, but does that mean cross country, technical single track, or rail trails? Are there lot's of elevation change(s) where you could be cooking on the downhill sections and cornering hard at the bottom/at speed?

The Make/Model of the bike might be helpful info here as well.

Generally you need a 19mm wide hooked rim to run a tire wider than 2" (maybe even 1.95" depending on the setup (tubed vs. tubeless). A wide tire on a narrow rim 'could' be dangerous if run at low pressures (20-25 PSI instead of 35-40 PSI) when cornering, but it would depend on speed/cornering load. At higher speeds/cornering loads the tire 'could' potentially roll off the rim as the sidewalls are quite rounded on a narrow rim.

As you can see, it depends!

I think it's the depends and ambiguity that gets me. And if there is any risk, I assume it gets higher as the tire ages (I've been riding unaware of this concern for several hundreds of miles by now).

Tubeless ready but I'm using them with tubes (puncture resistant so a little thicker). I've been using about 25-30psi. Usually around 30psi.

Some up and down trails but I'm not cooking downhill or taking aggressive corners - I'm not using the outside lugs and leaning heavy. Wheels are on a Rockhopper 29er.

So, the tires could be unsafe if I'm riding aggressively, leaning heavily, especially at lower pressure.

But I'm using moderate pressure (25-30psi), low speeds (less than 15mph) and not taking corners/turns aggressively (not leaning heavily and not using the side lugs much).

So, sounds like while the tires may not be really indicated, with my mild usage, it's probably okay? Maybe I'll try to add some pressure and keep it around 30-35psi; I'll try it and see if I lose traction.

I tried out 26" 2.1" tires - even w/ a decent tread, it's a no-go for the trails. It couldn't hand the sand portion. Very squirmy and stopped the bike. I can get through w/ the 29" 2.4" Ardent.

I guess it comes down to: 1) take the risk and keep using the 2.4" Ardent; 2) buy a new bike. Used Al might be okay; I'm really hesitant w/ a used carbon bike.

It seems like the two main choices are: 1) Spend money you don’t want to spend, and 2) rock on with what you have and try not to go crazy worrying about it.

I’d think it depends on where and how fast you ride and whether there is vehicular traffic around to run over you if something goes south.

My approach would be to learn what I can about it, then decide whether I can ride what I have without going nuts worrying about it. If I can, I’d probably do that. If I can’t, I’d spend the money to get something I can ride without worrying about it.

Your Mileage May Vary.

Good luck in working out a solution that works for you!

Yup; that's where I'm at.

I'm leaning toward buying new/used but perhaps at the beginning of spring. Hope there will be good sales at that time.

There is a good sale right now but it's the end of the season. I may not ride much during the winter.

Narrow rim+wide tire seems a recipe for pinch flats. Are these sizes of tires designed to resist sidewall compression?

My bike experience is with road bikes where, for the most part, the skinnier the tire, the better due to reduced rolling resistance. I'd pump up my sew-ups to 120 PSI or so to get the best roll. The biggest tradeoff was short tread life (like they had much tread to begin with), and sideways slip-skids during tight cornering.

The Ardents have EXO which is supposed to offer better sidewall protection.

Maybe you should talk to the shop that installed the tires and see what they say about the safety of the setup.

Updated OP with new query.