Chaps, Just a quick question for you all - hopefully I can get some feedback rather than just nonsense opinion !! :wink: Last year I ran a set of Dunlop NTec slicks for two days on track - fab tyres. But I then had some mechanical issues and the bike didn't get back on track last year from June onwards, so these were then sat in the garage since June (not cold, just ambient room temps). They do show some signs of blueing - a product of the oils coming up - but not too badly. They got hot, went through a couple of heat cycles, but were fine on the two days I ran them. Tread indicators show at least another two days use in them. On a web search as to whether or not they were still OK to run, I came across an official Dunlop tyre rep replying to another question by someone on this topic saying that the blueing was irrelevant, that race tyres contain more oils than standard road tyres, and that they would scrub up in two laps. That the only real issue was the tread remaining, and that tyres "harden" as they wear down, rather than as a result of oils leaking out - unless they got far too hot or were damaged by very cold temps. He also said that all tyres blue to some degree (at least Dunlop ones) and that it was just a fact rather than indication of anything really. I have another set of D211 slicks on another bike that also did only two days then went in the garage, and they are similar but slightly less blue.... Anyone else have a view? I came across loads of people saying that once they were blue they were for the bin, lots who said not, lots of conjecture, but this from Dunlop. I also just wondered if they weren't used for almost a year if that mattered at all. Usually I would run a set for four or five track days, then bin and change, it's just that these only did two days and then were left as the bike was out of action....... Easy option is just to junk them - but at 350 a pair that's a few quid to just waste if they are still good for three more days as the Dunlop chap says...... Any racers out there or anyone else with a view?
from the little i know on this , apparantly - as i was told from a pirelli high user - have 6 heat cicles in them. therefore it is important that hey stay heated all day as this is one cycle... a lot will depend on your setup and track temp as i ve seen cold tear throug a pair of SC2's on 1 day.. i did 3 days on a rear and it's still looking good...; so i gues it is very rider dependent...
I'd trust the Dunlop man's advice. Personally I haven't had a problem with tyres that have 'blued'. As they said, a couple of laps and you'd never know.
I do competion hillclimbs and use one set of tyres thoughout a season (power cups this time) and my tyres go through 5 heat cycles a meeting with at least 6 events a year, plus a possible further 2/4 depending on whether I bother doing them. They are scrubbed to the edges and blued and still grip extremely well. I get a new set every year because I believe its not worth risking thowing the bike at the wall for the sake of £250,the price I paid for a new set of cups with my club discount. I reckon last years tyres have only done 500 miles (power ones) and would be an excellent used tyre for street use or novice and maybe even inters use.
The English NTEC KR's are great tyres. Only two days use with a moderate rider and they will be fine. Use the wear indicators and feel as your baseline. They will scrub in again after a couple of laps. As said, keep them on the wamers all day and give them at least 40mins on the warmers before use.
Tried the power cups last weekend and had real trouble getting my tyre warmers over the tyre and between the swingarm ,probably due to a pointier profile. When I changed my chain to 520 I didnt allow for that so there isn't mushroom for adjustment. Now i'm a tad concerned I'll shorten the life of my new tyre warmers .DoH ! But although the road temp was 7degrees and the wind was blowing the heat from the tyres even though I'd chucked a towel and jumpers over the warmers which only got the temp of the tyres up to 58 they were grippy enough to get my knee down. So I've ordered those purpose made blanket things to enclose all the wheels. only did 4 runs so only 4 heat cycles. :biggrin:
Only one heat cycle if you keep the warmers on all day. It sounds like you need to add some links to the change to allow you clearance too.
Yep cranks I'd like to add links and will look to see if possible ,depends on my rear sprocket size and how many links. as for keeping warmers on just once it's not possible they have to go on every run and you have to wait at top of hill for all competitors in that run before returning to pits, can be half an hour especially if some car numpty bins it and the wrecker has to cart them off
A run is not a cycle . One heat up on the morning through the day is one cycle. Warm them up at 8 am and keep them warm till 18:00 is 1 cycle .. Don t let them cool down ..
Thanks guys. FYI, these are the two links I found from him, and he is the national US tyre distributor for Dunlop. Heat Cycles - Tires - Cornering Forum Tire Surface Bluing - Tires - Cornering Forum both of which made interesting reading, but your would hate to see your pride and joy skittering down the road for the sake of being a little tight on tyres.......
Although I agree with you there kopey its impossible in my disipline. 1 run is 1 heat cycle it is impossible to keep the tyres up to temp once the run is finished and your up the top of the hill waiting for everyone else to finish ,then you have to return to pits . Not letting them cool down is not an option. It's for this reason I get a new set of tyres for every season even though they've only done minimal mileage
If the surface looks good, and you've still got life in them I wouldn't worry about blueing listening to the treatment they've had. There's nothing looking at them can do really though. Next event either take spare tyres or the money to buy some there. It's all in the feel. I've had torn to shreds michelins that felt great all day, and had perfect looking bridgestones that slid more and more before going in the bin still looking good with plenty of life on the indicator. You'll know within a few laps if they need changing.
