Is this tyre normal? (Sidewall crack)

RocketMBA said:

Last week I bought a 27x1.75 "DSI" (Halfords brand) tyre and after less than 30 miles of cycling it's got these two cracks in the sidewall. I've taken a photo and circled them in red.

Is this normal, or is this £11.99 tyre going back for a refund?

Well, without having the tyre in front of me, I would say that what you are describing as "cracks" are some MOLD LINES/(whatever) which you simply did not notice when you first bought/mounted the tyre which are now apparent due to some road dust.

Maybe they are cracks ...

But, IMO, a "crack" would reveal itself as NEGATIVE SPACE in the sidewall/tread/wherever.

Thanks alfeng 🙂

What exactly do you mean by "negative space"? The "cracks" I'm seeing are a couple of mm deep and flex/move when the tyre is deflated, if that helps any...

photo is not good enough. Take a closer, high resolution photo.

If I were to GUESS based on what I see - which isn't much - I'd say they look more like scratches than cracks.

But, you need to take closer/better photos.

RocketMBA said:

What exactly do you mean by "negative space"? The "cracks" I'm seeing are a couple of mm deep and flex/move when the tyre is deflated, if that helps any...

A "hole" is "negative space."

I agree with Camilo that you need to post a different/better picture because the current picture doesn't reveal anything that isn't superficial.

IF, by chance, you ran the tyre against a "road hazard" and consequently you cut the sidewall, then you should not expect to receive a "free" replacement.

Thanks both of you - I'll post some better pictures A.S.A.P 😄 I just want to be sure that it's safe to ride on!

Alright, taken another picture of me putting pressure on the tyre and the crack/split/cut/whatever opening up and showing its insides. Hope this helps! 🙂

PS: if the forum downsizes the original image due to its size, it can also be found here: http://img697.imageshack.us/img697/8444/dscf08021.jpg

I hate to be a nay sayer but it looks as if it were cut. But hey, I'm making this judgement from a photograph. Anyway, it isn't normal as far as I know. Take it back to where you purchased it from and see if they will replace it.

Thanks kdelong 🙂 How would a tyre have gotten cut on the sidewall? I've ridden it twice (only owned the tyre since the 13th) and all of the rides were in the dry on very smooth cycle paths. Is it cool to ride on this tyre, or are we moving into blowout territory here?

Agree it looks like a cut. Could have happened while opening the packaging with a knife, or while someone was opening a case of tires with a box-cutter which went too deep through the cardboard, etc.

If the tube bulges the tire in that area when fully inflated then it's not something you want to ride, as the structure of the tire has definitely been damaged in that case.

Thank you frenchyge! I'll take it back to the shop tomorrow and see what they say - if they've had anything similar coming back in the past I expect they'll change it.

I don't see any bulging in the area, but I'll keep an eye on it and, ultimately, go for a higher quality tyre next time! 🙂

A better photo would be desirable but it seems a cut to me. When you pass over tiny stones on a road with your tyres well inflated, many times the stones are spitted to the side of the tyre -specially the rear- making a distintive "clang" when they hit a guardrail. If that's what happened while you were rolling on broken glasses, these could have done such cuts. (Roads are dirtier near the towns than in the countryside)

That is ugly but not worrying. What supports the tube pressure is the fabric underneath the gum. If only a couple of its threads had been cut, just by fully inflating the tube, a small but distinct lump would appear.

Thank you agotangelo for your expert input! 🙂 Will a cut in the sidewall like this cause the fabric underneath to weaken sooner, or anything like that?

RocketMBA said:

Thank you agotangelo for your expert input! 🙂 Will a cut in the sidewall like this cause the fabric underneath to weaken sooner, or anything like that?

I don't know, I once only had a slight deformation in the center of a 23mm slick road tyre but never on the side. I put some 300 km on it before i decided to replace it but it was on my front wheel and I never put more than 7 bar (101 psi) in it.

Your tyre seems to be 28 mm or wider so it holds 6 bars or less. Look at it once a week and replace it if you see a bulge (the cut is long, and if some threads get broken more can follow) but I wouldn't be worried unless you have it on your rear wheel and you weight more than 180 lb.

Cheap old tyres such as Michelin World Tour had thick sidewalls. Now I have the more comfortable Transwold City with 3000 km on them without a single flat but I have the dynamo sligtly low, and now I can see the brown of the side fabric. (I've put a rubber band around the dynamo wheel)

Hmm... It IS my rear tyre, and I'm a big fat 230lbs... It's 32mm, by the way, and I tend to put 80-90lbs in it. Is there any surefire way of telling if the fabric is cut? I considered shining a light through the cut to see if any light comes through - good idea/bad idea?

RocketMBA said:

Hmm... It IS my rear tyre, and I'm a big fat 230lbs... It's 32mm, by the way, and I tend to put 80-90lbs in it. Is there any surefire way of telling if the fabric is cut? I considered shining a light through the cut to see if any light comes through - good idea/bad idea?

Discard the tyre inmediately if you can see light through its side!

My guess is that if the fabric is cut, some bulge would be seen at 90 psi. I haven't dissected any tyre but in the publicity drawings, there are always at least two layers of fabric on the side, so -in theory- the outer could be cut and the inner still make the wall opaque to the light.

You can do a static test a couple of days by lefting the wheel swollen to 110 psi, (inflate from the opposite side of cuts 😉) and if all looks right, I would swap the rear tyre with the front one, and inflate them to 85 and 75 psi. I always put less pressure in the front wheel because this one bears less weight. I think that would be safe enough, and if the fabric threads are uncut but weakened, the side would break progressively and with enough warning, instead of suddenly.

All this are guessing because I never had a cut on the side of my tires!

There is no bulge at 90psi or 110psi... I took the tyre off and gave it a good inspection and no light is coming through, no fibres are visible, so I'm going to say that this tyre is going to be okay.

I'd stick this tyre on the front, but the front wheel is 8mm smaller than the rear, so it'll have to stay on the back and put up with my massive weight. If you never hear from me again, you'll know that the tyre failed and that I am no longer with you 🙂

RocketMBA said:

Is there any surefire way of telling if the fabric is cut? ?

Yes. Inflate to max pressure and look for bulging along the cut. No bulge - no disastrous cut in the fabric, which means rideable for now. The fabric may still have been nicked though, so it might start bulging there eventually.

RocketMBA said:

I considered shining a light through the cut to see if any light comes through - good idea/bad idea?

You'd be better off shining a light down into the crack, and see if you can spot any threads emerging through the sides or at the bottom. The strength is in the cloth, not the rubber.

Thanks for the advice dabac - I'll be sure to keep an eye on this one 🙂 Tyres are a fascinating subject.