180 or 190 profile on 6 inch rear rim?
 

What is the best tyre size to use on a 6 inch rear?

I'm looking to get some new wheels (c'mon Roy!!) and have a few part worn 180 rear SCs lying around that I'd like to continue using. (I think that Roy has been using 190s?)

Can I get away with these? Will it slow the turning a bit, or is this pretty much unnoticeable?

That's assuming that fitting a 180 to a 6 inch rim, will pull the tyre wider apart and effectively flatten its profile????

Ta
Tim :frog:

i would have thought 190/55 would be the way to go.

I run Michelin Race 2 180 rear on a 6 inch rim without problems, even at race pace. Mind you it did spin up at around 140 down park straight!:o

Like you say.....
 

I'm sure DJ uses 190's on his 6" rims.
I'll be reverting to 180's when I've worn out these OE 190 Pilot Sports. :barfy:

Thanks for the responses.

I reckon I'll stick with the 180s and see how I get on then.

But she doesn't turn quick enough as it is!!!

I'm thinking of changing the steering angle - as adding too much rear ride height, gets the back end a bit too lively for my liking when getting on the gas early out of corners!!!

Tim:frog:

Tim,

I've run a 180 SC2 Supercorsa and then a RS2 Rennsport on my Mag Marchesini 6.0in rim...the turn in is noticeably quicker than the ol' 190 I previously used.
I was told that fitting a 180 to a 6in rim would have the effect that you mention (flattens the profile) but I thought I'd give it a whirl and, yea, I did it and it was good.
Give it a whirl...what's the worst thing that can happen.........:sing::sing:...another muppet award????
Oh yes, I also run the steep head angle and have raised the rear...what's a bit of liveliness if it ain't a bit of fun???
Richard

[Edited on 7-6-2004 by RickyX]

The answer is.....
 

run a D208GPa Fatty :D :D

190/67/17 :o :devil:

FWIW I ran bridgestone and pirelli 180 on the 6" rim and felt like total shite, but a D208Gpa 180 ran fine albeit spinning up out of druids - fun though!

190/55 renns/SCs are the most popular choice

no expert and not having a go at anyone so dont chuck me out of the club:o.

but i cant see how fitting a 180 on a 6inch rim will make the turn in quicker, it just cant.

the reason i would guess is that the 190 profile was 50 and the 180 profile was 55. ie a 'taller' tyre. even so when put on a 6 inch rim i would still feel there would be no quicker turn in compared to a 190 on a 5 inch rim. but i clearly wasnt on the bike and you were so clearly you have a better idea than me!

i still think a 190 55 would be better larger contact patch and a higher profile as well. win/win situation.

not sure if they do that tyre in road tyres but definitely in sc1/2 varients.

DD,

I have seen that info. about a 190/55 being "the" choice but very few manufacturers do a tyre in that size. Maybe only Pirelli/metzeler and then only in a supercorsa??

Ray

Dickie,

You've really got me thinking now....
Here are some thoughts that I have currently:
- I have never had a 5in rim so I cannot comment about 190/50 on that size rim (I don't think it is recommended?)
- I was comparing a 190/50 on a 6in rim against a 180/55 on a 6in rim
- 190/50 tyre height is 190 x 50% = 95mm
- 180/55 tyre height is 180 x 55% = 99mm
- Perhaps the 4mm additional height of the 180/55 results in a tiny increase in head angle and results in a perceived quickening of the steering?
- Although a 180/55 is not recommended for fitment onto a 6in rim, the "spreading" of the tyre is only 0.25in per side. I would expect that this change in angle of the sidewall would not be transferred to the rolling profile of the tyre since the connection between the sidewall and rolling profile is "flexible" (in engineering terms, the angular deflection is not carried around the corner as there isn't 100% moment continuity at that joint)
- my comparison was conducted by comparing a worn 190/50 against a spanking new 180/55
- part of being in the club is that we are all allowed to have our own opinions, and those opinions stimulate healthy debate - so no need to worry about getting chucked out !

Richard

[Edited on 8-6-2004 by RickyX]

[Edited on 8-6-2004 by RickyX]

It also depends on the profile of the different manufacturers tyres I reckon.

So the answer is ------------------- try it and see!!!

The part-worns I have are all Supercorsas 180 profile so I'll be using these anyway and will see what happens.

Thanks for the responses.

Tim:frog:

[Edited on 8-6-2004 by Rattler]

I'm chucking some part-worn 180's on a 6" tonight and then off to Cadwell on Saturday. I'll come back here with a completely garbled message about if they're different or not. If I go quicker I'll say yes, I don't then I'll say they're crap :lol:

Jamie
Are they SCs?

[Edited on 8-6-2004 by Rattler]

Yes mate, SC1 front, SC2 rear.

Nice one - I'd be interested to know your thoughts.

Tim:frog:

Thinking about going to a 190 on my mags as the rear is 6 inches wide. 180 was good on the std rims but wondering if 190 would be better on the wider set. Need new tyres for MOT might just get 207RR's again as they've been faithful freinds so far.
Heres a link that contains an article by Larry Kelly about the merits of each. Look under articles, it is also the source of the tyre weights information refered to in a old thread about getting the equivalent of free mags by changing tyres.

http://www.mad-ducati.com/

Some interesting stuff. Mmmmmm

So is Shazam really Larry Kelly ?, or just a preacher of his words........:puzzled:

wots rong wiv TT100`s?

Nothing wrong with TT100s, the perfect accompaniment to any RED bike ;)

For what its worth the Dunlop expert at Rockinham yesterday said that with a 5.5 rim the correct tyre is a 180
and 6.0 rim a 190.

FYI
I think that the rear wheel width is measured from the inside of the wheel rim (beading) and therefore not all supposed 6" rear wheels are 6", they are in fact 5.5".

So unless it specifically states that they're 6" on the rim, it may not be.
Tim:frog:

Sorry to dissapoint ya Tim but an inch is MUCH bigger than you think - evidently! :D

[Edited on 9-6-2004 by DJ Tera]

Who's complaining over 1/2", 12mm, 1.2cm:D

Ah - but 1/2" is the difference between the id and od - right????

See this: 180/55 SuperCorsas are recommended for fitment to 5.5 or 6.0in rims!
http://www.metzelermoto.co.uk/produc...port_E2003.pdf

Also, for the SERIOUS tecchy:
http://www.atnet.it/lista/paper83.pdf

Mama mia...

[Edited on 10-6-2004 by RickyX]

The lips (its gettin worse :lol:) on the wheel are about 3mm wide from what I remember - it's been so long (even worse :lol: )

[Edited on 10-6-2004 by DJ Tera]

My std rims ( 3 spoke ally) measure 6+inch ish on the outside width. The magnesium marchesinis measure more than 1/2 inch more. In fact they are not far off 7 inches in total external width. Can't be bothered to measure too accuratley but will if anyone wants the exact figures.

Stimpy - that's what I mean about the measurements - your 3 spoke brembos would officially be 5.5" and the mags would be 6" - in all probability. That's from the internal diameter measurement (id).

Tim :frog:

I measured my march-mags when they arrived and the internal measurement was dead on 6"

When did you get mags????
I thought you were too tight!!!!:o:o:o:o:D:D:D

Bought some off Jasper. Not a case of too tight mate, just the right timing :)

Well Tim, I can only say...WOW....what a difference mags make :o
And running a 180 on the 6" was fine.