Maximum Tire Width

[mtbmartyr]

I have a 2007 Specialized Epic Expert with Pararacer Fire 2.1 tires. I'd like to put some larger tires on it (up to 2.4), but I'm not sure what will fit.

I understand that one company's 2.1 will be different from another's (So I've been told).

I'd hate to order some bigger tires only to find that they don't fit.

Is there some more scientific method of determining max tire width other than physically trying on the tire? I looked around the Specialized site, but couldn't find any relevant info.

Does anyone have a similar bike? What sort of tires are you running?

Background: I'm looking to race at Michaux, and I was hoping to put on some bigger tires to make up for my inadequacy as a rider :). Tires that could do well in mud and on rock.

[jed]

The Epic is an XC race bike, so 2.1 is probably the max you can fit in there. I had 2 Epics, but I never ran tires larger than 2.1, because I'm a XC racer boy and generally don't run tires larger than 2.1 (for racing, anyway).

Having raced Michaux many times, I can say with confidence you will be fine with a 2.1 on the back. Run a bigger tire up front if you feel you need more rubber, you get more of the benefits of the larger contact patch, i.e., better control, with less of the drawbacks of increased rotating mass and rolling resistence.

A combo that might work is what I have been running all winter: 2.35 Kenda Nevagal up front with a 2.2 Kenda Karma on the back. The 2.2 Karma might just fit in there, it rolls OK and isn't ridiculously heavy, has a large air volume, and works great in Michaux-like terrain. The Nevagal will make a lot of noise on any hard surface and feels pretty slow but it will hook up, and once again, is not too heavy for what it is. I have been running mine tubeless with Stans all winter up at Gambrill, so far, so good.

Honestly, I just race on 2.1's up there, though, usually UST because they are durable, and usually a fast-rolling tread pattern unless it rains. Large knobs are not that great on rocks, and faster tires weigh less without compromising durability because there is less rubber.

[rciracing]

I have a 2007 Specialized Epic Expert with Pararacer Fire 2.1 tires. I'd like to put some larger tires on it (up to 2.4), but I'm not sure what will fit.

I understand that one company's 2.1 will be different from another's (So I've been told).

I'd hate to order some bigger tires only to find that they don't fit.

Is there some more scientific method of determining max tire width other than physically trying on the tire? I looked around the Specialized site, but couldn't find any relevant info.

Does anyone have a similar bike? What sort of tires are you running?

Background: I'm looking to race at Michaux, and I was hoping to put on some bigger tires to make up for my inadequacy as a rider :). Tires that could do well in mud and on rock.


Hard question to answer as tire pressure is going to play a factor. Plus riding style will play a factor too if you tend to lean into turn. If you have any tire rub on the inside of the chainstay, then I'd say you shouldn't go much wider.

[g_barr]

I have a 2007 Specialized Epic Expert with Pararacer Fire 2.1 tires. I'd like to put some larger tires on it (up to 2.4), but I'm not sure what will fit.
Since the Expert has disks, you should only be limited by the stock 24mm rims and the rear frame clearances. The front should be fine width wise so the diameter is the limiting factor.

From Sheldon Brown's (R.I.P.) Tire Sizing (http://www.sheldonbrown.com/tire_sizing.html) article: "If you use a very wide tire on a narrow rim, you risk sidewall or rim failure. This combination causes very sloppy handling at low speeds." You'll also note Mr. Brown discusses the disparity in tire sizing. The nominal outside diameter is 26-inch but the actual varies by manufacturer, rim, air pressure... Even if you measured your rear frame clearances (CL axle to BB or upper link) and multiplied it by two, you wouldn't be sure which tire would actually fit.

You won't find anything on Spec'd's site because they don't want you to put 2.4s on an Epic. They want you to buy the bike designed for wider tires. Their customer service will probably be more help. But I bet they'll tell you the Epic isn't designed for >2.2 - it's a XC bike for goodness sake!

Also keep in mind a wider tire can cause stuff to get stuck between your frame and tire more easily. So even if you could stuff a 2.4 in there, it is likely to get "stuck" by mud, leaves, sticks, small rodents... This is one of the reasons mud tires are typically narrow (1.8 or less). The second is to push through mush to reach firm trail.

So now I gotta ask - why are you such a H8er?

[silly_yak]

Try here:

http://mtbtires.com/specs/index.html

It has measurements of tires...

[tsunayoshi]

For what it's worth, I ride a Trek Fuel (XC/Race bike) and fit 2.3 Panaracers on the front with zero issues. The fork is a Manitou Skareb something or other.

I wouldn't do the same to the rear, they would definitely rub (I know because I tried).

I like having the 2.3s on the front, I run a lower pressure than the 2.1s and love how the front just floats over stuff better.

[jdpaddle]

I verified some info posted elsewhere about the fires measuring small. Indeed they do. closer to 1.8. and I really felt the difference. they ride harder then I was used to. Didn't like them. thought others love them.

It is frustrating that the tires dont truely measure what they are labeled. really makes shopping hard. As far as fit- All you can do is mount them up and see.

I dont have the fit concerns on my bike that you apparently have. But the tires I list below is from my personal experience and recent experimenting. They are all only about .2" wider than the fires. in my calculation that about .1" on either side. But as the others say if space is already tight then flex in corners may come into play.

Bontragers ACX 2.1 and XR 2.25 really measure 2.0. Fire 2.1 really measured 1.8. So other companys 2.1 will measure closer to 2.1 then the fires and will have more rubber and a softer feel- nice IMO. If you are after that sort of feeling and filtering from the rocks, many other 2.1 will do what you are looking for.

all you can do is ask around and or pull the trigger on some others. I have now had 4 different tires on my trek ex7. all say 2.1 or 2.25 and none were as small and hard feeling as the fire2.1. And the Bontager XR' 2.25 rolled as nicely and felt as efficient as the Fires even though they measured wider. THats what I was looking for. More rubber, efficient, lively feel.

I am now trying Nevegal 2.1 DTC which still only measure 2.0 but thats in keeping with the others I have had so it will at least be a fair comparison. I have high hopes. We'll see. I am appreciating I should possible go up a size next time

my $.02

[drevil]

If you haven't already seen it, Shiggy on MTBR has done a lot of measuring of tires:
http://www.mtbtires.com/specs

[jabberwocky]

As others have noted, FireXCs are pretty small, smaller than their rated size. I think all Panaracer tires measure small.

I don't know about your frame, but theres no real reason for any modern mountainbike frame to only have room for small tires. My Turner can clear damn near anything (theres a guy on MTBR who puts 3.0s on his for winter riding). I can't imagine any mfg would make a frame in 2007 that couldn't clear at least a 2.3.

If you are anywhere near Reston, feel free to stop by and we can try a few different tires in your frame to see what fits (I have 2.3 Exifwolfs and 2.4 Holy Rollers both mounted to wheels that you could try).

[BikerMiker]

Sorry to bring this up, but I would go to a BIKE SHOP with lotsa tires and tell them to put the biggest tire in there that'll fit. If it don't fit, have 'em put another one in. Or just drop it off...

You can fit a 2.4 WTB tire in the front. The superfast 2.55lt Weirwolf tire will probably fit too. Small knobs... That's a real 2.4 tire. You can easily get a solid 2.2 tire in the rear.

We have those tires in stock in Chevy Chase. Make Punga figure it out for you...

mike

[mtbmartyr]

"So now I gotta ask - why are you such a H8er?"

It was a result of my search for the ultimate sports drink, essentially a combination of espresso, coca leaves, corn liquor, and Gatorade. I call it......Haterade!

But seriously, thanks, everybody, for the advice.

Last question (for now): I do a lot of riding in the Shed and EF, and my tire choices so far have been based on sidewall strength: what will hold up to the jagged rocks and what will gash easily.

Certain tires (Specialized, Michelin) seemed to gash pretty quickly.

Others (Panaracer Fire XC Pros, WTBs) took a lickin' but kept on tickin'.

Are there other 2.1's that stand up well to rocks?

[BikerMiker]

WTB! I've had great luck with Spec'd tires too. I think these are the only tires that I have been running for almost 10 years...

Yeah, I'm pretty sure about that.

mike

[jed]

I prefer Maxxis or Kenda tires lately. I loved Specialized tires when I rode for a Specialized dealer... but Maxxis and Kenda are just as good. They have been holding up well for me. Specialized did too. I never really liked WTB's tread patterns enough to put up with the under-sizing and extra weight. You can get somethng just as good or better from Maxxis or Kenda that will weigh less and still hold up. WTB tires wear like iron though.

The best way to avoid sidewall tears in rocky terrain is to not try to run superlight tires with thin sidewalls; run something a little thicker. Larger Kendas fit this catgory, as do the mid-range Maxxis tires, the ones with the folding beads, but not the eXCeption series. Or run UST tires. Another big key to rocks is to go tubeless, you can run lower pressures, which not only helps traction and reduces pinch flats, it also gives you a little margin for avoiding sidewall tears because the softer tire can deflect farther before ripping when it encounters something sharp.

I will probably run a Kenda Nevagal 2.35 on the front with a 2.1 Specialized Rockster UST or a 2.2 Kenda Karma on the back.