Any suggestion?

[trumpy]

Back into biking after lengthy layoff (I stopped riding road bikes before some of you were born!). I have bought a near new Speed Four and love it - silly bike for an old fart but who cares! I do have a question on tyre pressures though. The bike is fitted with Bridgestone BT010r's (180/55 and 120/70) in excellent condition and the suspension is set to factory reccomendations. I did not get a manual with the bike (anybody got one I could peruse?) but searching on the net has revealed that the book says 36/42 for tyre presssures. These seem a little high but I could be wrong (according to my better half I frequently am). Having spent a year or five in single seaters I'm used to playing with pressures but I haven't had the bike long enough (3 weeks) to feel confident about changing things (ie. I might not notice any difference and then I would feel a right twit!) Any suggestions?

BTW; anyone travelling in the central N.I. region (read Taupo) if you need access to engineering facilities or a secure (fully alarmed) place to park your bike for a night or two contact me, I can help. We are only a couple of minutes away from the Race circuit.

[DemonWolf]

Welcome to the Site trumpy..... and generious offer of secured storage.. Great stuff. I'm sure there's lots of people on here to give you advice on the tyre pressures.

Once again.. Welcome to KB =)

[MSTRS:Me]

By crikey. You could be a right handy guy to know. From one old fart to another !! Tyre technology has changed heaps since you (and I) were young'uns. Those pressures are probably about right for your bike with a pillion on board. You might want to drop them a tad when on your own - say 35F & 38R

[James Deuce]

Those are the right pressures for those tyres on the Speed 4. There is a huge amount of debate in different places on the site about tyre pressures, but I always stick with factory defaults. Lower pressures will get the tyres heating up quicker for track use, but will make them "square off" in general road use. Makes for interesting handling and they'll also wear quicker.

Welcome to the site.

[trumpy]

Thanks guys, your help much appreciated.

[Paul in NZ]

Well if you REALLY want to be anal about it....

Reading Guzziology during the silly season, I happened to read the section on tyres. It didn't all stick in my mind, but there was some advice about setting the tyre pressures by trial and fang and measure.

The theory went something like this:

Think of a number between 25 and 50 Put that in your tyres and go for a (short) fang. Measure the pressure with the tyres hot. If it hasn't risen by 10% (I think, memory faulty) then drop the pressure by 10% and go for another fang. If it has risen by more than 10% then increase the pressure by 10% and go for another fang.

Repeat until busted for fanging around the shopping centre carpark or tyre pressure changes by 10%.

It made sense once but I was drinking...

[Ixion]

Ha. Welcome Mr Trumpy. Always like to see you young fellas joining up.

Veritable babe in arms you still are compared to some here.

[Will]

I have heard it said that if your tyre pressure differs by more than 5 lbs between hot( after a good ride) and cold (rest) that your pressure is wrong. Can't remember anything other than that though. Guess a bit of C.R.A.F.T. sneaking in.

By the way, check out www.ulysses.org.nz and see when Taupo have their meetings and rides. Great bunch of bikers.

[trumpy]

Those are the right pressures for those tyres on the Speed 4. .

Jim,
Could you tell me where you found that information? I have been running 36/42 since I put the tyres on the bike but since I was new to both the bike and riding on the road again, making an accurate judgement of performance at various pressures was not really possible (no problem if I had two more wheels and on slicks!). Nearly 5000ks later it's a different story (sort of!). Recently did a KB ride to Ohope and set the pressures to the recommendations for OEM tyres (P/P's, 014s ) in the owners handbook(34/38) but found, the back, particularly, squirmy and by the time I got home they had started to square off. Up to then they had been wearing quite evenly. A couple of hundred K's at 36/42 seemed to clean them up again (or is it just the extra pressure changing the shape?).
Did 300ks today at 35/39...better than before but rear still moving around a bit. Having spent the last four years on a dirt bike, this does not bother me, but I am not sure whether these tyres (Conti Attacks) need to be run at these higher pressures (36/42) or whether I need to be looking at other factors (me, suspension settings etc) for better performance.
I know what I think but I am looking for wiser counsel than me. Any suggestions?

[nadroj]

Stick to 36/42. The new tyres work better at this. BTW Busa's 42/42.

[EZAS]

what should I run my 95 ZX9R at then?

[James Deuce]

I got that off Bridgestone's website, and I used their suggested fittings matrix.

[trumpy]

I got that off Bridgestone's website, and I used their suggested fittings matrix.

Thanks Jim. The bike feels much better at 36/42 so I'll ignore the owners manual and stick with those pressures.

[Devil]

I run mine at the manual recommendation with the OEM BT010's. 34/38 (was running 34/36 before. I use 36/40 with pillion). I'm just about to tick over the 10,000km mark with those tyres (pilot powers next). Get your suspension sorted.

Noticed recently that the rubber has gone off on mine and the back end started feeling a bit squidgy despite using the same pressures. Your tyres might just be old.

[trumpy]

I run mine at the manual recommendation with the OEM BT010's. 34/38 (was running 34/36 before. I use 36/40 with pillion). I'm just about to tick over the 10,000km mark with those tyres (pilot powers next). Get your suspension sorted.

Noticed recently that the rubber has gone off on mine and the back end started feeling a bit squidgy despite using the same pressures. Your tyres might just be old.

Checked sag the other day and is set similarly to your bike, the other suspension settings are on the factory "standard" as per the manual. I will probably have a play with those over the weekend. First up I may drop rear compression slightly (like you I have been bounced off the seat a time or two) and then go from there.
I have done about 5000ks on the tyres and they appear about half worn. They have been on the bike since november.
Will keep the pressures as they are for the moment (at least the bike is predictable like this) then play with the suspension. Once that is done I may play with the pressures again. Learnt the hard way in my first year of racing single seaters to only change ONE parameter at a time!