Grooved slicks: Road legal or not?

**idleidolidyll** · 14th February 2007, 17:00

I'm interested in using slicks on my road bike grooved to the same pattern as a mainstream tyre manufacturer's road tyres.

Is this illegal and if so why?

Does this affect insurance policies? Given that a well grooved slick would be stickier than a road tyre, can they argue safety?

Tryes are just too bloody expensive in NZ. In the UK I can buy tyres for about 30% less than in NZ (same tyre).

I see no reason for that except gouging and that's why I'm interested in grooving up slicks.

Are there any other options? (group imports etc)

**Motu** · 14th February 2007, 17:03

Are they DOT or other approved standard? If so then that's fine - if they are not approved for road use then they are not approved for road use.....

**idleidolidyll** · 14th February 2007, 17:06

Originally Posted by Motu

Are they DOT or other approved standard? If so then that's fine - if they are not approved for road use then they are not approved for road use.....

That might answer the legality question but not the insurance one.
I'd suggest that insurance companies couldn't argue that they are unsafe but if there is someone out there who has had an accident wearing grooved slicks on the road; please tell me what your insurance company thought about it.

Frankly I don't give a rats arse about the cops; they usually only check the tread depth anyway.

The COST (RAPE?) question is still unanswered too.

**Kickaha** · 14th February 2007, 17:19

Originally Posted by idleidolidyll

That might answer the legality question but not the insurance one.
.

If you're using a tyre that doesn't meet an approved standard for on road use what do you think the chances of a insurance company paying out are?

**svs** · 14th February 2007, 18:40

no, they're not legal. slicks are specifically stamped NHS (not for highway service)

your insurance company won't buy it. just get DOT legal tyres. the pirelli supercorsa pro are as sticky as slicks anyway - and DOT approved. ask andew stroud.

**Toaster** · 14th February 2007, 18:41

mmmmm grooved slick.......

**Bloody Mad Woman (BMW)** · 14th February 2007, 19:02

Originally Posted by idleidolidyll

That might answer the legality question but not the insurance one.
I'd suggest that insurance companies couldn't argue that they are unsafe but if there is someone out there who has had an accident wearing grooved slicks on the road; please tell me what your insurance company thought about it.

Frankly I don't give a rats arse about the cops; they usually only check the tread depth anyway.

The COST (RAPE?) question is still unanswered too.

I had grooved slicks on my bike - and they had "not for highway use" I had an accident, no-one picked it up - admittedly I had totally forgotten about it. Now the bike got assessed by the Insurance co. and by the bike shop - it was only when I got it revinned and re-registered that I was told they would not pass.

(my bike was written off and I bought it back from the ins. co.)

When pulled up by a copy - they have never noticed either - as long as the tread is good.

**Clivoris** · 14th February 2007, 19:08

Wouldn't slicks cost more than road tyres to start with? I'd also be worried about maintaining good temperature on the road too.

**idleidolidyll** · 14th February 2007, 19:11

Originally Posted by Bloody Mad Woman (BMW)

I had grooved slicks on my bike - and they had "not for highway use" I had an accident, no-one picked it up - admittedly I had totally forgotten about it. Now the bike got assessed by the Insurance co. and by the bike shop - it was only when I got it revinned and re-registered that I was told they would not pass.

(my bike was written off and I bought it back from the ins. co.)

When pulled up by a copy - they have never noticed either - as long as the tread is good.

Cheers, that's about what I thought.
I reckon there are also some shops and assessors who KNOW that it's actually safer (if the slicks are cut well).

**idleidolidyll** · 14th February 2007, 19:13

Originally Posted by Clivoris

Wouldn't slicks cost more than road tyres to start with? I'd also be worried about maintaining good temperature on the road too.

Used slicks so no

i don't think temperature is a problem; just run the right pressure for the day/ride. i pretty much do that anyway, i check my pressures (and change them if needed) almost every ride.

**Mr. Peanut** · 14th February 2007, 19:58

Have you seen the Shinko 003? It's a Yokohama clone, fairly sticky, cheap ($300 for a set), but the profiles a bit flat.

**Spyked** · 14th February 2007, 20:01

What sort of life could you expect? Soft compound and already used, the frequency of tyre changes would likely be a pain in the ass.

**scumdog** · 14th February 2007, 20:19

Originally Posted by Spyked

What sort of life could you expect? Soft compound and already used, the frequency of tyre changes would likely be a pain in the ass.

And... and.. would you REALLY notice the difference in performance?

Compared to the Corsas mentioned above?

**Ixion** · 14th February 2007, 21:20

From the WoF VIR manual

Sect 10-1
Reasons for rejection
...
12. A tyre not identified as designed for regrooving has
had its tread depth increased by regrooving.
..

And as putting a groove where none was would certainly be increasing tread depth, a fail

Though whether any inspector would ever notice is another matter.