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Wednesday 18 August 2010

New tyre

I have just replaced the rear tyre of the Bonnie. The last run around South Wales killed off the old one - tread in the centre was non-existent.

I ordered a new one from Pneus-Online, a firm I haven't used before. The tyre arrived yesterday and it went on today, no problems. Most web suppliers were asking £100 to £120 for a Metzeler Lasertec 130/80/17, but these people were doing it for £72 with free delivery. At that price, it would be rude not to.

I took the opportunity to do a bit of housekeeping at the same time. I took the rear shocks off the bike, to allow the swingarm to drop fully and make it easier to get the wheel out. While it was out, I did a surgical clean of the swingarm area, which is usually hard to get to, and gets caked up with black chain grease and general road crud. Once it was clean, I brushed on some Waxoyl to the bits I know I can never get to during an ordinary cleaning session. The swingarm is only painted, and it's in the way of a lot of spray and grit from the rear wheel, so a bit of heavy-duty protection isn't a bad idea. The Waxoyl is matt-black anyway, so it doesn't look out of place.

I also cleaned up the wheel while the tyre was off. The Bonnie wheels are really nice, with chrome rims, stainless spokes and very shapely cast hubs. A bit of time with Gunk and a paintbrush, then a hosedown, made the wheel look great. In fact, Anna had a look out of the window and asked if I had been buying new wheels. It all went together again with a dab of grease here and there, Loctite on all the essential bolts, and a tour with the torque wrench to finish off. It looks fabulous.



I had a bit of a challenge with balancing the wheel. I had bought a pack of wheel weights and used the jig that I had made when I rebuilt the XT rear wheel last year. The weights came in 5g and 10g varieties, but I found that the 10g were too wide to fit on the flat area of the rims. I ended up using all the 5g weights, and even had to stick a couple of 10g ones on the flat between the spokes to get the balance perfect. When I get some double-sided tape I will rescue the old 5g weights and stick them on in the correct place, and take off the 10g ones, as they look distinctly odd. The theory is that you mount the tyre with the red spot adjacent to the valve, where a slightly lighter part of the tyre will counter the extra weight of the valve. Then weights will need to be added either next to the valve or directly opposite. In my case, the weights had to go at 3 o'clock to the valve position, which is a bit strange. No worries - the wheel now has perfect static balance.



I went out for a few miles to start scrubbing in the tyre and the bike felt much better. The handling had started to get a bit wayward as the rear tyre flattened off, but it is back to the usual precision now. And the gearchange is much better now that I have adjusted the chain properly - it was getting a bit slack, but I didn't bother doing anything about it as I knew it was all coming apart soon anyway.

It is recommended that new tyres are scrubbed in by taking things gently for about 100 miles, and gradually increasing the lean angle until the whole tyre surface has been roughened up by the road and all the release compounds scrubbed away. I think I got about half-way to this in 15 miles. I now have inch-wide chicken strips, which are due to be slimmed down over the next few days. Should be fun.

The rear tyre went from 3.5mm tread in the centre to zero in 2000 miles. The tread on the new one is 7mm, which implies a tyre life of 4000 miles. But I have always found that tyres wear far more quickly towards the end of their life, so I hope it will be a bit more than that. The front has gone from 3mm to 2mm in the same period, so it won't be long before that will need changing too. The tread looks very clear and defined, but when you get close there isn't too much on there. That will definitely be replaced before winter.

4 comments:

  1. I paid £94 for a similar size Bridgestone BT45 fitted to my K75 at a local "sole trader" working in the garden chap - so you got a good deal!
    I was a bit taken aback at the prospect of "bias ply" tyres after radials but I don't see any great drama...hopefully.

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  2. I think it was a cracking deal. I was a bit nervous as the tyres are sourced from anywhere in Europe (mine came from NL) but it's a standard tyre, not a second, and it seems to keep the back end from dragging on the floor. I like Bridgestones, though - the 020s I had on the Pan were superb. I was going to try the 2:1 thing with the Metzelers (new front every two rears), but I don't think I will get away with it.

    I can't say I worry too much about bias/crossply/radial. If the tyre is designed for the bike and works well, then that's OK by me.

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  3. I don't think I have ever, in my entire life, owned a wheel that beautifully clean!

    Had a look at the website mentioned and they're a bit of a mixed bag - looks like you got a very good deal on the Metzeler. The Bridgestone BT014s or BT020s don't look quite so much of a bargain, though: about the same as my local dealer charges if buying a pair. Possibly. I got a little lost with all the price variations depending on "Technical information for the German market" codes that I couldn't quite figure out. Thought at first they might be speed ratings, but that's obviously not the case.

    Anyway, very nice job of cleaning.

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  4. Thank you! It's the first time I can remember that I have actually taken the wheel out before cleaning it, and I have to say it makes it very easy. Gunk and a paintbrush; light application of water hose; leave to dry.

    I didn't look at any other prices while I was on the site, but it is to be expected that they aren't consistently cheap. I'll be needing a new front tyre before long, but I will still Google for prices, although I will go to Pneus-online first for a benchmark. A bit of a plus is that they sent me a customer satisfaction survey 10 days after purchase, which implies that they care about the 'customer experience'.

    ReplyDelete

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