Tyre trouble

[10uptobase]

Hi

As my original Avon ZV3’on the rear of my 150 roadsport were getting close to the limit and I had a two week holiday in Wales planned, it seemed prudent to change them.  The local tyre specialist informed me that Avon no longer do the ZV3’s and they had been replaced with ZT5’s so I had two 185 60 14’s fitted to the rear of the car – the same size as originally fitted all round.

On the way home I noticed the car tended to tramline / bump steer at speed.  A check of the pressures showed they were up at 30 PSI (despite me telling the fitter to put 20 in!)  I put down the instability as excess pressure and duly dropped them to 20psi.

I have now returned from the holiday and have to report the car is still the same.  IE fine at low speeds, but anything above 50 or 60 is quite unnerving (similar to when I had excessive camber on the front before I adjusted it.)

Anyone had any similar experiences?  Do I need a different pressure? Are these just rubbish tyres???

[SM25T]

I don't know these tyres ... are they directional tyres (markings on the sidewalls) ? If so, have they been fitted the right way round ?

[SM25T]

By the way .... fitters had to inflate my Toyo T1R tyres to 30psi to be able to balance them .... then released pressure back to my required 18psi. When they had tried to balance them at the operating pressure, they were adding weights all over the place as the tyre flexed.

[Julian H]

Reading the Avon description of the ZT5 it does not appear to be anything like the equivalent of the XV3! 

[DJ.]

A friend who owns a tyre fitters once told me that "ZV3s weren't very good tyres even when fitted to normal cars". Unfortunately, it sounds like the ZT5s are worse

If you're looking for some reasonably priced all weather tyres, I swapped to Uniroyal rain experts and have been really pleased with them. I've also heard good reports on Dunlop Street response.

Duncan

[RedCat7]

I've no experience of ZT5s but my ZV3s were much better at 17 psi than 20 psi.

[diggerman]

I also had the tramlining experience when going from ZV3's to much more grippy Yoko's. My experience was also quite un-nerving but was simply, and completely cured by getting the tracking accurately set up. I believe i had it set to parallel to 1deg toe out (or was it toe in) others may correct that figure. Memory a bit suspect!

Peter

[10uptobase]

My new A048 are fine as we're the old Avons. Good news is just put the new ZT5'S on the front and the ZV3'S on the rear and all is as it was! Only problem is when the other ZV3'S wear out!!!

[Ian B]

All I can add is a change to something like Toyo T1R's from ZV3s will be a complete revelation to you in the handling and grip!

As said above, a good seup from a caterham specialist will also likely transform the car.

[Martin J]

You have done well to wear the ZV3's out, they are are hard compound tyre really not suited to a light weight car, they made my 7 feel nervous in the wet & the driver even more so. 

I mourn the passing of the Yokohama AO21R  but have enough spares to keep me in tyres for at least a couple of years.

[Dave Hardcastle]

Ian, can I ask what tyre you used before? Are you still using the Toyo?

I ask as I currently have Avon CR500's on but would rather change to a more readily available tyre.

 

thanks in advance

[SM25T]

This Ian used CR500 for years. Changed to Toyo T1R ... on 15" wheels. Third of the price. Lots of good tread pattern and depth. Lasting well. Fab at clearing water.

[6speedmanual]

CR500 is very readily available.

BMTR Birmingham

http://bmtrracing.com/contact/

[Martin J]

CR500 not available for 14inch rims.

[TomB]

So what's the current preferred substitute for 21Rs? 

[DJ.]

I've just done a Car Limits day at North Weald on my Uniroyal Rain Experts (185x14x60) and had a great time. Video here:

I certainly wasn't the quickest car, but for a low powered Seven, they're great on the road whatever the weather, and they have now done a Goodwood trackday as well as Noth Weald and still loads of wear left all for £150 for four delivered from Camskill

Duncan

edit, by the way, I didn't bother to post video of the times I didn't lose it as they were rather boring to watch

[Ian B]

Dave, I guess your question was aimed at me 

When the car was supplied it was fitted with ZV1s or ZV3s (can't recall which) on 14".

After a couple of incidents with very poor grip (mainly understeer as I only had a standard 1.6k and no LSD so not loads of power for oversteer), I changed to CR500s on 15" and the grip and handling were transformed.

I was happy with CR500s for years until the price started to get silly (c£120 a corner) so I looked around an found Toyo T1Rs in 15" in a choice of 45 or 50 prifile were only £50 a corner delivered, so I swapped to those.

Wet grip about the same as CR500s, clearing standing water better than CR500s, dry grip slightly worse than CR500s, but NOWHERE near as bad as ZVs.  I tried running the T1Rs at 15psi to get the dry grip better and that improved it, but at the expense (naturally) of quite increased shoulder wear. I normally had them at 19psi cold.

For a recent 2k+ mile tour to Italy I changed the rears to R1Rs. Was a bit of an experiment as I felt the back wasn't gripping as well in the dry as I would like with the T1Rs back at 19 psi.
Extremely pleased with the resultant improved grip of the R1Rs compared to the T1Rs.

As I don't have buckets of power (now just a 1.6k supersport) but I do drive it "enthusiastically" I think the R1Rs are great on the back, and will possibly change the fronts when they wear out. Having only done the 2k+ mile Italy tour on the R1Rs I can't really comment on the life, but then I don't buy tyres for the seven based on long life, I buy them for the best all round grip, at a sensible price  

[Dave Hardcastle]

Thanks for all the replies and apologies, I only noticed the 'page 2' button today!!

After posting my original question but before noticing the 'page 2' button I saw that there were two of you recommending them, so took the plunge. Demon Tweeks currently have them on offer, 195/45 x 15 for just under £40!

It will probably be next year before my car actually needs them, but I like to plan ahead, especially when it saves me money!

[SM25T]

That's a good offer !!

[Dave Hardcastle]

That's what I thought. I asked for the 2-3 day delivery and they still sent them Express24, i.e. next day. I was very impressed with price and service. With two members recommending I'm sure I'll be impressed with the tyres as well

Now stored in the garage for use when required. Even with good weather I think that will be next year.