Cut in my tyre

[Rhodrich]

Quick question - how bad does a cut in a tyre need to be before it's sensible to replace it?

I had a nasty puncture yesterday that has left a 1.5 cm long cut in the tread, that has also gone through the carcass for about 3mm. Now that the puncture has been fixed, on inflating the tyre, there is a noticeable bulge at that point, and the cut in the tread has opened out to a width of about 1mm.

I use the bike daily to commute (28 mile round trip daily), and I don't want a blow out at 30mph. The question is whether this damage is minor, and nothing to worry about, or major, in which case I'll replace the tyre.

Second question - if I do replace the tyre, are Zafffiro's any good - Planet X currently have the folding version at £7.99 in my preferred 700 x 28 size (which is the largest I can fit on the Mavic MA40 rims that I have), which seems like a pretty good deal to me.

[NUKe]

3mm is quite long and it could split further. As you say you dont want a blow out, but nearly as bad is having to fix the tube on a cold winter night.

If you are on a budget Zaffiro are fine, If your commuting everyday and can afford it, assuming you don't like the inconvienience of fixing punctures by the road side with freezing cold hands then spend a bit more on something a lot more puncture resistant.

Tyres everbody has their favorite, My Commute is equiped with Gatorskin hardshells .

[Brucey]

IME if you don't do anything about it that kind of damage will nip the tube and/or split further. You can use a tyre boot on that and keep on using it if you like ( some folk would aim to 'wear it out on the rear') but better tyres seem like a good solution to me.

cheers

[andrew_s]

Generally, you don't want to ride with a bulge if it isn't necessary.
A reasonably firm boot (I use sections cut from an old tyre) will stop the tyre bulging and allow you to carry on riding, but if the boot is too thick it can chafe through the tube and cause a puncture after a few hundred miles.

I generally use Gatorskins, but as I'm a sucker for a bargain, I'm currently using Giant PR-3 700x28, which cost me the princely sum of £11 for the pair. Seem OK so far, apart from being a bit over size (28.5 wide x 30 high).

[Rhodrich]

Thank you for the input everyone.

It does look like the safest thing to do is the replace the tyre, despite it only having about 500 miles on it. Very annoying when this sort of thing happens. I guess I didn't pay much for it - like you Andrew_S, I bought it from Rutland Cycling, although it's a Giant P-SL2, not an R3. They're supposed to be front and rear specific, but I have 2 spare rears, so I might just put one of those on the front, and see how it goes.....

For the distance that I do, I'd far rather have a more supple, less puncture resistant tyre, than a heavy puncture proof one. However annoying, having to repair a puncture once every few months isn't too much of a hardship. It is rare that a foreign object causes quite so much damage - I have no doubt that whatever caused this cut would have punctured a Marathon or Gatorskin too.

[Vetus Ossa]

It does look like the safest thing to do is the replace the tyre, despite it only having about 500 miles on it.

I think you have made the right decision.
You have to ask yourself, should you happen to be decending a hill at 50mph plus one day how confident you would be.

[thirdcrank]

Unless you stop using it till you have the replacement tyre, a boot would still be a good idea in the meantime. The spread of the split may be imminent.

The idea is to spread the pressure of the innertube evenly over a larger area of the outer to avoid it trying to go through the split and enlarging it.

Through my own neglectfulness as a teenager, I worked out a way to do this at the side of the Devil's Beeftub in pouring rain. I scavenged a bit of tarpaulin-type material from a roadside fly-tip. On another occasion (when the damage wasn't my fault) I used a bit of hi-viz cloth tape from some roadworks. Ideally, you need a strip 2-3 inches wide, and long enough to line the tyre with a bit to spare at each bead. When you refit the tyre line the outer with your patch of cloth and ensure a bit at each end is hanging out so that when you inflate, the beads will trap the cloth. It's important not to have it too tight or you will get a low bit in the tyre where it's not quite so well inflated. OTOH, the thin cloth will prevent a bump being caused by the thickness of the boot.

I'm surprised we've not had a post from somebody (meic, where are you?) who relishes making something like this last, but if you are concerned enough to ask, I doubt if you will enjoy your riding till it's fixed.

[meic]

I'm lurking somewhere, beyond the borders.

My philosophy is roughly so long as a tyre's fibres are intact, I am happy enough with a tyre.

I have ridden some tyres where the fibres have been cut or have just broken and they can take hundreds of miles to fail, it is slower at first and then accelerates as more fibres are failing. Two of them were Schwalbe Marathons a tyre constructed as solidly as a motorcycle tyre almost.

In this case the rider is considering a new tyre at £8 and has a daily commute which no doubt he doesnt need to replace a blown out tyre on. I recently replaced a Marathon Racer before doing an Audax because it had a similar wound and bulging, I rode it for a few hundred miles in more relaxed conditions but not for the Audax.

If you do ride it then I would (and do) carry a replacement tyre for when it goes. Also it may not just puncture your inner tube but make it beyond repair and did the tyre have enough value in it to risk that too? Not in the case of my Racer.

If you are carrying on with it, then fit a boot of some sort, carry a spare tyre (and tube), fit it on the rear. You dont need to inspect it that much as you will feel the lumpiness in the ride as the bulge is growing.

[thirdcrank]

Sixteen minutes. That's bordering on spooky. Good to see you're still on the ball, meic.

[Rhodrich]

Thanks again all.

New tyre fitted last night from the parts bin. It is supposed to be a 'rear' tyre, according to the label, so I'm not sure what effect it will have putting it on the front - it certainly doesn't seem to be significantly different, handling wise from the old one.

I've looked at my spreadsheet, and the old one had actually done 879 miles. What a waste. I guess I've only had to bin 2 tyres in total in the 5000 miles I've done so far this year on my various bikes (the sidewall blew out on one of my other Giant P SL2's after 2200 miles)

I'll buy a pair of Zaffiros to keep in stock for the next incident. I don't think you can go wrong for the price.

[[XAP]Bob]

New tyre fitted last night from the parts bin. It is supposed to be a 'rear' tyre, according to the label, so I'm not sure what effect it will have putting it on the front - it certainly doesn't seem to be significantly different, handling wise from the old one.

You'll go backwards - although since it sounds like you have a rear tyre on the rear as well you'll either go sideways or fly straight up in the air...

[Rhodrich]

So... another tyre, another cut. This one's only got about 800 miles on it. Note the slight bulge, and tufts of tyre cord sticking out:



Looks to be terminal again.

What are the forum's current recommendations for economically priced tyres in 700x28c size that are reasonably durable, but not too heavy? My philosophy is that I'd rather repair a puncture every 1000 miles or so than to ride round on heavy tyres like Marathons.

Are Conti Ultra Sport II tyres any good?

[Brucey]

you'll most likely get as many opinions as there are tyres that size out there....

If you are routinely slashing/cutting tyres like that then you are most likely riding over broken glass; if you can't see it and avoid it then I think you perhaps ought to go for a heavier weight tyre, at the rear at least.

BTW if you run a slightly wider tyre (a 32 will often be an actual 30mm on a narrow rim) then you can run it at slightly lower pressure which means certain types of tyre damage are made less likely.

cheers

[Chris Jeggo]

I find that Gatorskins roll better than Schwalbe Marathon Kevlar, and are pretty robust. My rear tyre that is nearly worn out has some nasty-looking gashes in the tread, but the next, protective mesh layer has done its job and the carcase is undamaged - no bulges.

[Rhodrich]

This is my commuting bike. In 30 miles a day across central London, in the dark, riding over broken glass is unfortunately inevitable. Perhaps going up a size might be a good idea. I did 2000 miles over autumn on Conti Top Touring tyres (the supple mid 90's version, with no puncture protection), and I had no punctures or cuts on them in that time. They are 27 x 1 1/4 though, so a 32mm width. Last winter, I was riding on Continental SportContact II tyres, again in 32mm width, and had no punctures or cuts.

So it seems to me that the problem is that these tyres are just too soft/lightweight for commuting, especially in these dark winter months where glass avoidance is impossible. I can't say I like Gatorskins, but they may be a better idea.

The only problem with wider tyres though is that these rims (Exal XR1) only have a 13.4mm width: