Tyre Damage : Doh!

Okay ... so I am stupid. Yes, I do cherish my bikes ... yes I know them intimately ... Of course I do!!!!

This afternoon I showed the very helpful Jason up at Halter's Cycles and it turns out these are wear indicators; ie: they show how much the tread is worn. Clever, huh?

So thanks Jason. I will buy something worthwhile from your really rather good bike shop some time soon.

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* see my Bike Index here

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Tyre Damage : Continental GP4000

Can anyone identify this tyre damage or possible flaw?

This Continental GP4000 tyre has done about 200 road miles at 120psi on the rear of my bike. I weigh about 190lb.

I noticed this after climbing a local hill which has been recently relaid. At the time I noted to myself that the blacktop seemed to incorporate a lot of what appeared to be glass granules, about the same sort of size / appearance as glass from a broken windscreen. The glass definitely appears to be a part of the surface, not just pressed in by traffic.

I don't normally ruminate about the composition of road surfaces, but in the last couple of days I had been listening to an article on NPR which stated that low grade glass is recycled for road surfaces ...
So anyway, at a coffee stop, not a mile from the hill, I happened to notice these rather odd pock-marks, rather as if a miniature ice-cream scoop had gouged out the tyre compound. The cut seems very clean.

Now I can't say for certain that this had only just happened, but I had just checked / adjusted my spoke tension / wheel trueness just a couple of days before and hadn't noticed any damage.

Does anyone have a clue what's happened?

Otherwise, I love these Contis. And yes, I can spell tyre ;-)

Bike 04 : More About Punctures ... or not

Well, so far so good. From the point of despair; ie: a puncture every twenty miles or so, I've now pedalled well over 100 miles without incident.

Undoubtedly this is down to two things:

1. Continental GP4000 tyres - cool website ...
2. Sludge tyre sealant - hmmmm ...

Anyway, cool websites or not, these are two products which do exactly as they say on the can.

Firstly, the Contis.

These are very nice tyres indeed. Handmade in Germany and an obscene price here in the States, fortunately they're available from the UK at a much more sensible price, which my LBS tells me he can't even match here in the US at wholesale.

The first big plus is that tyres can be pumped up to 120psi, but despite that feel much smoother and more comfortable than my old tyres pumped up to 100psi.

Further, the shell fabric, called Vectran, is employed as a breaker belt, which I assume resists punctures, also combines with the high pressure to make for a tyre with a very low rolling resistance. It was noticeable in the 5 Boro Bike Tour how I would just drop away on even the slightest descent leaving the people without hand made, German tyres in my wake.

Next, Sludge. What an inspiring name. Okay, so it's as good a name as Slime, the local bicycle tyre sealant. And of course, who knows if it works or not, because if it is working, you'll never really know ... However, I enjoy the sense of security it gives me, and that's a good thing. 50gms isn't a lot to add the weight of your bike for that sort of confidence. Besides the Contis are probably 50gms lighter anyway. And you really can pour it in through a presta valve. thus using any inner tube you like, even those very fine latex racing inners.

As I said, as to whether this combination works in the long term remains to be seen. But I'm pleased so far.

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* see my Bike Index here

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Bike 01 : First Ride Of The Season ... and punctures

Well, last week I went out for an hour or so. And today I rode for two hours. I covered close to thirty miles. Not bad considering ...

I was using my road bike, the Trek 1200. As I've mentioned before, I ride a frame smaller than normally recommended for someone of my height - 1.90m / 6ft 3". This means the seatpin is pretty much at full extension, and I've rotated the stem 180 degrees to raise the bars about 50mm / 2in. I feel pretty comfortable with the result.

The real problem with cycling here isn't the standard of driving, although some drivers seem to have homicidal attitudes towards cyclists, but punctures.

I know one of the complaints in the UK is that roads aren't swept enough, but here they don't seem to be swept at all. Given too, that road surfaces aren't nearly as good as you might suppose in a country where the whole economy seems to be driven by the automobile, frequent punctures seem to be the cyclist's lot.

So this year I gave some thought to alleviating, if not solving the problem.

Tyres : I am trying Continental GP4000's. This tyre uses a new material, Vectran, which is supposed to be more resistant to punctures and have better rolling resistance than Kevlar.

In addition, I'm trying some new tyre sealant, Sludge, which has been specially formulated for application through presta valves. In the case of the Continental inner-tubes I am using, the core of the valve unscrews anyway, making application even easier.

On the road, the extra 50gms of sealant in each tyre feels insignificant, but the Contis are a revelation. Despite being pumped up to 120psi, they don't seem to have the teeth-rattling effect my other tyres had at 100psi. Not only that, the tyres seem to hold their path well, even on tight corners. It will be interesting to see what they're like in the wet.

On the downside, the Contis are very expensive here - about the cost of some car tyres. You might get a better deal from PBK in the UK.

The 5 Boro Bike Tour is only a matter of a couple of weeks away ... I'd better keep this up.

* PS : Yes, I know how to spell tyres ...

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* see my Bike Index here

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