Tyres...

There's interesting reading on the BHR forum ref Max rim sizes and tyre sizes. Many a different point of view too. Luckily on a Bantam you can run whatever rim size or tyre size you like - which is very easy to police!? I know most bants run WM1 or 2 width and 18" Wheels.

Pete after your success with the new Avon 90/90 AM22's how do you rate them compared to the Dunlop KR825's and come to that the 17" wheel and tyre you tried on the front a couple of years ago.

And Phil Betty/Mike Redhead your 17" wheels/tyres do you have to run WM3 rims??

Alan what about the heideiu (spelling wrong) are they still availible? they were well soft I remember...
Please comment...

Whoops that should of been AM26 not 22

Hi Mike,
The heidenau tyres were good and soft and the sizes most suited to me, but they are not too great in the wet, brilliant in the dry though! However they are somewhat difficult to obtain in race compounds now as the distributors are few, and as you know I couldn't get them at a price that was viable and got into a bit of an argument with the factory!
Supply would have been cheaper via the internet from Holland! I will be watching what happens with Pete's tyres and the progress with Avon...
Alan

This is a hard subject to comment on considering that we have no ruling on type or size, mainly it all comes down to confidence in grip,cost (wheel building rims and tyres)and availability.

I remember when I started racing 12 years ago I had new 18inch Avon road runners, good dry and better in the wet but on a Sunday morning at Lydden after a lot of the bike not feeling very stable I changed to the Dunlops. I got quite a shock over 2 seconds a lap faster, and a lot happier.

10 years on i am still on the Dunlops and am happy 99% of the time in all conditions. I did think when we built the new bike about going to 17inch rims as there is more of a choice of tyre but looking at Dunlops spec for rim size (wm2 front and wm3 rear I think it was) decided against the change due to weight and clearance and the old saying if its not broke don't fix it. How ever after seeing Petes new tyres (a newer version of the roadrunner) I am thinking of trying the Avon's but only on the rear as it wont fit under my fork brace on the front.

How easy are they to get hold of and how much do they cost???

Ian you have a wm2 on the front of 008 anyway!! so weight would be the same? Was it the weight of a wm3 on the back you didn't fancy? Phil Betty/Mick Potter 004 is on 17's are they both wm3? with Honda type front tyres on - narrower than Dunlop KR825.

Arthurs SeeleyG50 which I ride did have a Avon AM22 but now has the same as Pete a AM26 but with a wm3 rim(not wm1) and it was fine!

Hi Mike, you are quite right, I am currently running a 17" Dunlop on the 175 but on a wm1 rim, this I was told by the tyre company SMD was the incorrect rim(too narrow), however as Mickey Nash never does anything without good reason I have never felt the need to question it, it does triangulate the tyre somewhat but this helps when cornering, and as I dont go fast enough to need the brakes this has proved fine! unfortunatley I am now told that that paticular tyre is no longer available and so I am following this debate with some interest, do I stick with 17"and go for a wider rim, or lok at 18" as an option?

The biggest problem I have with tyres is the spare ones round my waist, if only they could be reduced to 17" or 18"

Mike normally running a narrow rim means a smaller contact patch - so higher corner speed (scrubs off less speed) or if to small - you fall off as the tyre wash's out....
But with your 17" triangulating? perhaps you get a bigger contact patch? Which 17" tyres are you on ? Are they the same front and back?
Are they Dunlops whats the KR...number.
When running 18" WM1 (1.6 between beads) you don't get to the edge of the tyre where as you can with a WM2 (1.85).
When I've ridden bikes on 17's (Teds 125 aircooled and Paul Djurassi's ex Moulden machine) they don't wash out but let go, big time - then grip! High side's hurt more too on landing!
I'm sure there will be a replacement 17" tyre to fit?

Interesting (?) conversations at the BHR AGM ref tyres and rim sizes!! Luckily we are the only class with no resistrictions on tyre and rim size.... The unlimited class can run 130mm wide tyres now... we can run 170mm plus ....if you like!

<<Pete after your success with the new Avon 90/90 AM22's how do you rate them compared to the Dunlop KR825's and come to that the 17" wheel and tyre you tried on the front a couple of years ago>>.


Info for Mike

These new Avons are larger on outside diameter 619mm v. 600mm of the KR825. Thus a more rounded profile than the Dunlop, but the main improvement is the compound. Because the tread blocks are "slicked" i.e. larger area, a softer compound can be used. Unfortunately they are significantly heavier. 3.00 kg v. 2.2kg.

On the track they make the bike feel like its on slicks! The downside is the weight. Hauling it over to the left on the exit of the Gooseneck was an issue.

I dont know where you can buy them from as the front one was a prototype compound. Price is similar to the Dunlops, circa £120 each. They are hoping to improve the compound and reduce the weight if sufficient demand from us and the 250cc class. (Classic and Historic racing)


Regarding the Dunlop KR??? 17" front I used a 3 or 4 years ago, I couldnt trust it at the limit - the tyre would slide. Mind you I was still riding with the restrictive leathers then. So jury out on that one.

hope this is of interest.

pete

Pete,

Can you suggest a UK source for such tyres in a sticky compound ?

Local distributor has not got 90/90*18"s and others only in road compounds.

With the fantastic exchange rate of our $ to the quid its well worth while parallel importing.

There is a local Heidenhau importer, but they could not tell me what compounds are available.

So need some replacements for TT100 on 175 LS.

cheers

John

I think there was an Avon rep at Lydden ( I was too busy fixing bike to go and look ) - perhaps Gerry or Kim have a contact no. ? Or try Ken Inwood at Hersham 01932 229547, he's probably got a van full by now.....

Thanks for that Pete! its nice to have a tyre choice and you prepared to do the testing too... Hope a few more people try the Avons.
John is there not a Avon race tyre importer in New Zealand?

Just received the following info from Avon Motorsport:-

The 18” AM26’s I used were a pre production test set. They are now producing 100 of each specs (compounds) for general sale. Size is 90/90 x 18.

The softer compound tyres (13984C) are now in stock, and the medium compound tyres (14310C) will be in stock by the New Year.

Sounds like the the lighter front is still some way off.

The tyres will be available directly from the factory (at Melksham, Wilts) or via one of Avon's racing tyre dealers

http://www.avonracing.com/supplier_locator_page.aspx


John Sendall: The above link shows the NZ agent is in Hamilton, is that near you?

<<Thanks for that Pete! its nice to have a tyre choice and you prepared to do the testing too... >>

Thanks Mike, but it was really a nostalgia trip for me.

In March 1984, before the first BRC meeting of the season (at Mallory), I tested Avon road Runners in racing compound via Sones Tyres. They were good and as you mentioned elsewhere, I went on to beat Mr Pell's jockey for the Championship. Mind you, I am sure we were on the Dunlop K81(?)s at the time.

Next iteration in tyre (Mid 1985) was the Michelin T23? on the rear , which was just like a hand cut slick.

I cannt remember the exact type numbers, but am sure someone will be along who can.....

Hi Pete,
I have a great memory for all things Bantam and recall Mick Cashmore was on hand cut slicks in 1983!! They were Michelin's front and rear i remember that because they had the dimples at 120 degrees and the cuts there uneven and square bottomed!! Everyone else was on TT100's K81 as you say.
In 1984 the ACU out-lawed hand cut slicks at club level so produced 'factory moulded slicks' The rear a TF23 the narrower front TC21? Were made...These were only about for 2 seasons before Michelin decided to (try) make club racers (and ACU) have wets and slicks and no intermidiates (TF/TC). In 1987 the Dunlop KR825 came out just at the right time and Michelin missed out! Then of course Honda RS125's went 17" wheels etc etc

Thanks Pete and Mike for your help and interest.

Yes there is an Avon Race tyre importer, thats Dold Industries, the one you saw in Hamilton.

They are only wholesale, I asked through a dealer, they only have 90/90*19 AM26s or the old AM20 in 18" (the 110/90 a bit too big for rears)

Small market, usually only one big order/container before race season.

So I will try Avon directly or a UK dealer.

But it also sounds like it maybe worth waiting for the lighter front and or medium for rear.

cheers

John

Dunlop KR825 Compounds - for reference :-

soft/medium - 950

medium - 523

Hi Mike,

Are these actually current Dunlop?

Pete

They are the current ones my tyre supplier has, I haven't spoken to Dunlop.

Quote Mike - "I have a great memory for all things Bantam and recall Mick Cashmore was on hand cut slicks in 1983!! "

Mike I tried a slick a few years earlier. The rules simply stated that slicks were not allowed for club meetings. So when I turned up at Lydden with a slick on the rear that I had got hand cut with just a couple of zig zag lines. There were crys of "cheat" and "they are not allowed" from other competitors. But the scrutineers had to admit I was bending the rules not breaking them.
I don't know if it was because it was the hardest compound intended for Donington (a grippy circuit) or if the Bantam never produced enough power to put heat into the rubber, or possibly Just me not knowing how to get the best out of it.
But I do know that after a few slow and hairy laps of practice. Both my underpants and the tyre were changed.

Ned - didn't notice you on a cut slick - but it wasn't on for long....
When Rick and I got the bikes from you and Tom 001 had a full wet on the front and a michlin on the back but the number 2 TT100's all round. In 1987 I had 001 on Kr825s and 002 on full wets!! I felt like a professional!?

For those of you on old Dunlop Kr825's or if you have bought a bike with some on some info:-

To date read read 4 figure number, the first two numbers are the week the second two the year so
1105 is 11th week of 2005 and 4310 is 43rd week of 2010...

Compounds some years they change some years they don't? Oh! its the 3 digit number by the way
180 hard
789 soft
420 hard
440 soft
654 soft
622 hard
564 soft
325 medium
950 medium/soft
758 medium
523 medium

Regards Mike

Here's the last bantam to wear a hand cut slick - a bridgestone (ex- Keith Woods) in 2005 breifly Lydden Hill Saturday only. The tyres on the newly revamped 002 were replaced by Scutty's Avon road runners on the Sunday...

[quote="mjpowell"]Here's the last bantam to wear a hand cut slick - a bridgestone (ex- Keith Woods) in 2005 breifly Lydden Hill Saturday only. The tyres on the newly revamped 002 were replaced by Scutty's Avon road runners on the Sunday...


I recognise that rear end. It currently wears a KR825 in 950 compound. The Avons are hanging on the garage wall.

'scuse my ignorance, but what is a tyre "wash out" all about ?? They won't fit in wiv my sox'n'nicks...

Chris

Ref Michlen Tyres of old:-
TF23 Rear size was 10/63
TC21?Front size was 8/61

Anyone know what the 10/63 etc meant?
Peter any idea?