View Full Version : Tires

07-10-2008, 04:07 AM
Ok here is the set of rims I bought awhile back.

http://cgi.ebay.com/NEW-ATB-WHEEL-SET-DISC-READY-WHEELS-26-WTB-TIRES_W0QQcmdZViewItemQQcategoryZ58089QQihZ010QQit emZ200221193710QQrdZ1

And these are the tires I found.


Will these tires work ok for the rims I have.

I know nothing about bicycle tires so i need some help to not make a bad purchase.

Papa will the tires you put up work ok with these rims.

And if I buy tires that are like 1.5 will I need different tubes , or will the tubes they sent me work.
Sorry Im a newb at bicycle parts.

Thanks guys


Pagan Wizard
07-10-2008, 04:50 AM
The rims are 2.1 inches wide while the tires are inly 1.25 inches wide. With the wider rims, you'll need wider tires. If my failing memory serves me well, the tires you use should be within .25 iches of the width of the rim.

07-10-2008, 07:24 AM
I found this article by Sheldon Brown to be of great help when I was trying to figure out what the minimum width of tire I could put on my road bike was a few years ago (Roadies think that way lol).


07-10-2008, 01:43 PM
The rims are 2.1 inches wide while the tires are inly 1.25 inches wide. With the wider rims, you'll need wider tires. If my failing memory serves me well, the tires you use should be within .25 iches of the width of the rim.

PW, the post lists the tire size as 2.1", not the rim. I've yet to see a modern 26" rim, either aluminum or steel, that isn't 1" or thereabouts for aluminum and 1.5 or so for steel. Come to think of it, I can't say as I've ever seen a rim wider than that, not to say they don't exist.

I've had tires as narrow as 1.3" (my current Schwalbe Marathon Slicks, 1500 miles and counting!) on up to 2.2 (Serfas Drifters, tough but HEAVY) on the same set of rims on my C'dale, which measure about 1" wide between braking surfaces. No mounting issues, although I've found with the smaller tires they're a bit 'fussier' to get mounted, the beads are quite tight.

Obviously, tube requirements change with tires, no sense stuffing a 1.75-2.2" tube into a 1.5" tire. I run 1.25-1.75 tubes in my Marathon Slicks, and they leave plenty of room for my Mr Tuffy strips. I run the Marathons at 65-70psi, and ran the Drifters at 50psi. I also ran a set of no-name foreign dual-sport tires (waffle pattern in the middle, lugs on the sides) at 60-65psi, I think those were 1.75 or 1.95, I forget.

07-10-2008, 05:04 PM
Ok now I am even more confused.

Just measured my actual rim width which is about 3/4".

The specs on the rim say 26x18mm which is 0.7086614173228347".

So that is just less than 3/4 of an inch.

So if 26x2.1 fit on this rim why wouldn't the 1.25 or the 1.5

If I had to be within .25 inch wouldn't I actually need a 26x1 .

I hate the way they do tire sizes, both fractional and decimal.

I have learned that fractional 1 3/4 will not interchange with 1.75,
even though I would think they would be the same.

Confused even more


07-10-2008, 09:18 PM
Ok last question I had is about tire pressure.
I read on sheldon browns website( good info there even if somewhat Dated).

That higher pressure tires= less rolling resistance, therefore easier to get rolling and keep rolling.

Question is at what tire pressure does the tradeoff between less resistance and more tire bounce = worse handling and bouncy ride.

I have these 2.1 raptor knobbys running at 55 pounds max is 65.

Do I need to get the tires that will go up to 100 psi, heck I saw some that go to 160 psi.

If 60 will get me a decent ride.

Bear in mind I am 350 pounds plus bike weight of about another 70 pounds.

Distributed over 3 tires thats about 140 pounds per tire, actually on the delta would be more on the rear because of the lower center of gravity,
Putting more weight on the rear wheels "I think that's correct".

I think I will go with papa on those 1.5 metros then switching out to my knobby's in winter if I decide to ride in foul weather.


07-10-2008, 11:58 PM
Thanks learning more every day I am here.
So a nice 26x2 slick would be a good choice.
Or middle of the road 26x1.5.

Getting a better understanding finally.

Thanks again PAPA


07-12-2008, 06:34 PM
Just bought those Irc metro 26x2.0 on ebay.
Thanks for the link.


07-12-2008, 06:44 PM
I can't remember where I read it, but some roadie gurus say you can safely over-inflate most tires about 20%, since they have a margin of error built in. I routinely run my 85 psi road tires about 100 psi, without any problems.

07-12-2008, 08:47 PM
And you are willing to sacrifice that margin?... for what reason?

Personally, I don't see any point in exceeding the 'max' recommended pressure on fatties. Remember; the wider, more volume the tire, the less psi it needs to support the same weight. Then there's the rim sidewalls to worry about... especially after the brake pads have been grinding on them for a year or two. Sorry... not on my rigs.

Apparently I am lol- on my skinny road bike tires, at least. Why - I am cheap and like to go fast. I have had blowouts on my road bike at 25-30mph with no ill effects, but its always PITA. I don't recall any of them being sidewall blowouts, usually just very rapid decompressions.

You raise a good point though, and I am not sure I want to be responsible for anyone else doing it. Its always better to recommend being conservative.

07-12-2008, 08:52 PM
I can't remember where I read it, but some roadie gurus say you can safely over-inflate most tires about 20%, since they have a margin of error built in. I routinely run my 85 psi road tires about 100 psi, without any problems.

I always run ALL of 'em at 5 psi over, even car tires, unless they have noticeable dry rot.
I figure that's a small enough "fudge factor" to easily still be safe.
Just tryin' to get that tad less rolling resistance...


07-12-2008, 09:10 PM
Yes, same here with car tires - been running 40-45 psi since I learned how to read a gauge. But... with a car, I am held-up with 4 tires, instead 2 or 3, and I'm surrounded in a steel cage.

But papa, wouldn't you say that a blow out on one wheel of a car at high speed is much more dangerous than one on your bicycle? Remember the Ford Explorer and Firestone tires! Granted most of those deaths were stupid operators slamming on the brakes, or whipping the wheel, but you never know when your wife will be driving.

In one of my former lives, I was involved in reading thousands of accident reports on those Explorer/Firestone blowouts. You would not believe the dumb things many of he drivers did when the tire blew. Many of them were also caused by under-inflation, which causes the sidewalls to heat up excessively.

My wife and I were recently traveling in a van on the interstate going about 70 mph, when a relatively new Michelon tire suddenly gave up the ghost on the rear. She was driving and I noticed the car swinging violently from side to side, but she wisely just held it as straight as she could and let it coast to the side of the road. It sure reminded me of what some of those stupid (some now deceased) Explorer drivers would have done instead.

Moral of the story - train your family members on how to handle a blow out on a car.

07-12-2008, 10:54 PM
The reinforcement in car tires is much greater than average bike tires, which seems to be what most of us use. A few pounds over in a car tire is much less likely to cause a blowout than a bike tire.

07-13-2008, 07:18 AM
Good thoughts as always papa - and something for me to reconsider the next time I check the tires on my road bike. I am not sure how much speed I really gain anyway from the extra 15 psi and I don't race as much as I used to.


07-13-2008, 08:54 AM
The reinforcement in car tires is much greater than average bike tires, which seems to be what most of us use. A few pounds over in a car tire is much less likely to cause a blowout than a bike tire.

That's true. That's why I personally, only go over by 5!
Better 5 over, than 5 under, IMO.


07-13-2008, 11:19 AM
to add a bit in...

most properly engineered things that have limits (weight, pressure, etc) are designed to handle 3 times the amount of stress that the warning sticker says. course, it WILL fail, collapse, explode, etc if you put that much stress onto it.

ive seen car RIMS explode from being overinflated and overloaded.

personally, im always scared to death to actually put 60 psi in those skinny tires on my road bike. just seems like something that small and skinny wont be able to handle that much pressure.

as for car tires, a neat trick ive heard of- inflate to what you think is right, then use a crayon to draw a line across the tread. drive around the block, and see where the crayon line has worn away. adjust tire pressure accordingly.

07-13-2008, 11:29 AM
I think that modern equipment is designed with less room for error than in the old days. Modern computing power now makes it easier for designers to get on the edge.

When I was in college I took a mechanical engineering course commonly called "Vibrations." It covered such things as taking vibrations of such things as crankshafts into account in the design. My professor had worked on the old P51 Mustang design during the war. He told me that after they designed anything using all the equations we studied, they went to a handbook and looked up how much extra to add to it to make it really work lol. The "extra" was based upon experience with things breaking. It kind of took away some of the faith I had in engineering as a mathematical science. Now I think a lot of the things designed in China to sell to us have material subtracted instead of added lol.

07-13-2008, 02:32 PM
Gm says there are strict specifications that have to be met by the manufacturers of their parts in Malaysia, and those specs are the same as when they were made in the U.S. But how can they monitor quality control?

07-13-2008, 04:21 PM
Hmmmm...recently a TOY distributor lost a bundle over lead paint....trusted overseas manufacturer to meet rigid guidelines...guidelines are like Locks...only keep honest people honest...

Yes, there are built-in margins that do exceed recommendations/limits...there is also an "acceptable" failure rate %... The more one crowds the limits, the closer one comes to the failure rate %, yes or no?

If you inflate five % over recommended 32 psi in a car tire...that's 1.6 psi? on a $1.99 plastic air guage with a + or - 10% accuracy rating...no real big deal, but same situation on a 110 psi bicycle tire...kneeling down with face on same level as sidewall of the tire....inches away from your eyes....hmmmm, I had a new tube blow out the other night in my garage...ears rang for two hours...

I have no earthshaking points to make here, just passing on some random thoughts.

07-13-2008, 07:17 PM
I had a new tube blow out the other night in my garage...ears rang for two hours...

Eh? What's that you say sonny? SPEAK UP!

Seriously though, when pressures approach 100 psi, I'm a little leary myself! Good points! :)


07-13-2008, 07:19 PM
Okay. So now we know we need to add earplugs or headsets to our list of safety equipment.

07-13-2008, 07:32 PM
And NEVER put a tire over 40 PSI on those composite "mag" wheels. I have heard that they can split in half and sent glass-like shrapnel all over the place.


07-13-2008, 09:14 PM
As we go "Safety Serious" for a moment, Brad is exactly right!
We sometimes forget just how dangerous compressed air can be! From time-to-time we need to be prudent while having fun and at least thoughtfully examine safety perameters...(sp?)

Yeah, I know, Evil Knevil never let anything like "prudent forethought" slow HIM down!!!!!! Methinks his bones healed faster than mine, his insurance was better, and as for pain threshold??? I'm a wimp.:o


07-14-2008, 03:10 PM
Just thought I'd add my 2 cents...

Ditto to the 'crayon across the tread' trick on cars. Back in my day, we used chalk, you only had to roll it two or three revs of the tire (ie, a car length or so) to find the 'high spot'.

NEVER inflate over the tire pressure marked on a car tire- those are MAX LOAD ratings! Read it: "MAX PRESSURE 32PSI AT 2,000 LBS". That means, for THAT ONE TIRE, IF it is loaded to 2k #, you should run 32psi to keep the sidewall straight. Your whole CAR only weighs 4k #, and you have FOUR TIRES!

I used this rule of thumb on my Jeep: The Jeep weighs 3650#, add my 200# to it and it's roughly 3850#... round up for misc and call it 4k#. Okay, I had 31" BFG All Terrains, rated max pressure 50psi (I can't tell you how many times I had to air down after getting a 'full service' oil change... :mad:) at 2k# max load. Four tires, that's 8k# load capacity at 50psi. I don't need 8k# capacity, I need 4k. So, half load, HALF PRESSURE, or 25psi. Because of relative weight differences (engine, cargo, etc), I ran the fronts at 28psi and the rears at 24... oddly enough, EXACTLY what it says on the door sticker!!

Why do I mention this? My wife bought those tires in 1998 to go on her Jeep CJ-7, and ran them for three years, about 20k miles. We transferred them to my Scrambler when we got a set of mud tires for her '7, and I ran them for a couple years, maybe 15k miles. When my Scrambler got mud tires, I transferred them to my Jeep Cherokee, and I ran them for AT LEAST 40k miles (it was our highway vehicle, and my daily driver). That's a total of 75k miles, more than any maker's warranty!
I just sold that Cherokee last year, with those same tires on it, and they had better than 50% tread life left. I used the exact same equation on every vehicle, always kept them inflated properly and rotated. For all I know, the kid who bought my Chero is still running those tires.

As for bike tires, I run them comfortably WITHIN the rated pressure range. I tend to run on the high side, to reduce rolling resistance, but always within. I just aired up this morning, 70psi. The Schwalbe Marathon Slick is rated to 80psi.

Another thing to take into consideration is your rim. Single-wall rims typically can't handle higher pressure the way doublewall rims can. Case in point: a cheap spare rear rim I bought for my C'dale keeps breaking spokes at the nipples. A quick inspection of the inside of the rim near the valve hole noted: "MAX PRESSURE 50PSI". I had been running at 70-75psi! Whoops! Ran the tires at 50, no more broken spokes. Then I switched to the Schwalbes, and changed to a double-wall rim. No worries.

07-15-2008, 06:01 AM
My new Irc metro 26x2.0 tires will be here weds.

Can't wait to see the difference.

Knobbys bounce a lot at higher speeds.

Thanks for the link papa.

Looking forward to smooth tires and a less bouncy ride.

And lower rolling resistance and easier takeoffs.


07-16-2008, 02:12 PM
I can say is fricking WOW.
These IRC Metro's are SWEEEEEET.
I can't beleive a set of tires would make all that much difference.
I thought the ride was good on those KNOBBY'S.
What the frick was I thinking.
Takeoff is so much better.
The ride is so much smoother.
And Coasting wow it will roll forever.

I think I got some ummm Wood from my ride.
Or maybe it was because of the half naked chicks out by the Pool.

Only thing I know is I love these tires.


07-16-2008, 08:10 PM
Just don't tell the mountain bike guys that ride on my trail. I need all the advantage I can get lol.

07-16-2008, 11:22 PM
Oh my now im in the neo-**** bike riding party.
Inflated them 2 60 psi, they were still squishy with all my weight.
Put 70 psi it is perfecto.

Thanks again fellow skinhead,