Shahmatt

...and they now seem to be bulging and warped.

I can't see if the wire bead has separated. I'm at work right now and can't check. I've let out some air to prevent it from getting worse.

This would be my front tyre - a 20" Kenda Kwest 40psi (1.5" I think).

I've got a spare new 20" Kojak which I can use as a replacement, but I really want to check if the Kenda can still be used. For reasons as follows:

1. I don't need a high pressure tyre up front
2. It's really comfy for the wrists (I use straight handle bars).
3. I absolutely love the reflective sidewalls
4. Wider tyres would seem to me to have better grip during wet conditions

I will try deflating the tyre and re-inflating, hoping that the tyres bulge only because they've lost their seating on the rim. Got the following question though:

1. If the tyre wire beads are damaged, but still retain the shape for use under the low 40psi pressure, would it be unsafe to use?
2. Has anyone here gone from Kenda's to Kojak's (90psi) on the front tyre? If so is there a large compromise on wrist comfort?

Artkansas 

Just buy another Kenda, then. The tire's bulging because the cording is dying. This could become dangerous if the tire blew in the wrong situation.

Yes, it is unsafe.

Eric S.

I had a fairly new Vittoria Zaffiro bulge at mile 80 of a century ride last year. It lasted those final miles, but the abnormal shape caused the area of the bulge to wear down rapidly and there was cord showing at the finish.

AusTexMurf

Try the newer 100 psi version of the kenda kwest.

rebel1916

Why are you intentionally over inflating your tires?

Erwin8r

I agree that it will be dangerous (especially on the front...). As another has mentioned, the chords have stretched/are dying, so why prolong the inevitable?

cooker

Tires can appear to bulge if the tube inside is bunched up, so make sure it is not just that. But if it truly has a weak spot get rid of it.

hubcap

Weird coincidence. Because of a tire bulge on one of the stock Kendas, I recently switched to Schwalbe Kojaks on my 20"-wheeled Mercier Nano. I love the Kojaks. No wrist discomfort. They seem to roll a lot nicer than the Kendas.

PatrickGSR94

Whoa, how many miles were on the tires when that happened? I just took off my bike's original Zaffiro tires with about 1,600 miles on them, only because I got a great deal on Conti GP 4-seasons, and I'm just keeping the Zaffiros in the garage as backups. One of them does have a small cut in the middle of the tire tread, which I filled with Shoe Goo and never had any issues in the nearly 1,000 miles that the cut was on there.

ThermionicScott 

Just because it has a higher max pressure, doesn't mean you have to pump it up to that pressure. Doubling the front tire's pressure would definitely "compromise" your wrist comfort.

dynaryder

Kenda lists their 406x1.5" as having a max of 100psi,so I doubt you over-inflated it. It could have just been a defective or old tire.

Kojaks have a range of 55-95psi. Note,they're only 1.35",so a bit skinnier than the Kwests.

Eric S.

They were only about 1 month old. I bought them mail order for $15 each so it was too much trouble to return the defective tire.

noglider 

This is a salient point. The right pressure for you depends mostly on the tire's width and your weight, not the tire's rating. See the tiredrop.pdf file that floats around the net.

Shahmatt

I usually re-inflate at a LBS. They have a free air hose just out front which is convenient. There's no gauge on it. The pressure on the hose is at around a 100psi, but I take care not to put too much into the tyre. This was accidental really. I've learned my lesson. I think I'll use a floor pump with gauge from now on.

The Kwests come in a 40psi version and 100psi version. I have the lower pressure one.

I removed the Kwests and looked carefully on the inside but could not find any damage on the cording at all. It may be that the damage would appear on inflating.

Anyway I needed a tyre for this morning's commute and did not have time to experiment. So I went ahead and installed the Kojak. Tried it out this morning, and I have to say it seems to roll pretty decently. It is ever so slightly faster than the Kwest. It is also a tad less comfortable but surprisingly not overly so.

I'm a little worried as to how the Kojak might react to road drain grills. The Kwest is wider so there's no chance of it getting stuck, but the Kojak can slip inside. The tyre won't get stuck but it's still a minor hazard.

I will probably try out the Kwest again over the weekend. I don't want a good tyre to go to rot. :-/

Ridefreemc

I have replaced 6 Kenda Kwests and am ready to replace another - all with the same issue that you described. These replacements/bulging were not due to over inflation either. They are a terrible tire in my estimation (lots of experience with these for my family of 5). I also have them on my folder and quickly replaced them because they were not round (bounded along as opposed to rolled).

Pay a few extra bucks and get something safer and better. You don't want to get stranded with a blown tire.

chas58

+1

The optimum pressure for a tire is based on tire size and weight on the tire. You can ride the 100psi tire at the same pressure as the 40psi tire if they are the same size (not gonna guarantee the 40psi tire will hold more air than the high PSI one).

The 100psi tire should not give you worse ride quality if you use the same size and pressure as your old tire. It might be better because it may have a more subtle sidewal.

The marking on the sidewall is based on the physics (size and intended weight), along with intended market (race vs comfort) and with better tires, testing and evaluation. Most people are better off running the minimum tire pressure in the front tire, and for the rear something in the middle between max/min.

PeterCB

Can I over inflate a Kenda Small Block Eight tire? Limit says 50 psi. Can I take to 55 psi for a road race?

acidfast7

I had Kenda K191s on my bike what I bought them and they were crap. Flats all the time, however, they were cheap at $7/tyre.

I wouldn't buy another Kenda tyre.

FBinNY 

PETER,

It's been 4 years, and I'm sure the OP replaced his tire by now.

Meanwhile, you can safely exceed the max pressure limit, because there's generous safety margins built in. So go ahead, but next time please start a new thread for a new question.

acidfast7

Also, I'd like to point out that there was no damage to the tyre but it would bulge below the suggested max psi as described above.

Never buying a Kenda again.

Digital_Cowboy

I'll ask the question that it appears hasn't been asked yet. Why are you over inflating your tyre?

noglider 

Jobst Brandt claimed that tire manufacturers test their tires to double the recommended maximum. Not that it's a good idea to use that pressure, just that it's unlikely it will blow.

Trakhak

See post #5 (from 2013).

DiabloScott

In fact, the tire company that he consulted (and posed for advertising photos!) for, claimed that most rims would rip apart at a lower pressure than the tire would blow off.

acidfast7

My Kendas didn't "blow up" per se, the slightly deformed and didn't roll flat.

Never buying another.