Correct size slicks
#1 _MAWLER_
Posted 01 February 2006 - 04:45 PM
I'm getting ready to cut my diff and square up my wheel tubs and so have to pick the size rim I want to try and squeeze under there. From what I understand the width and wall of a drag slick is supposed to be matched to the rest of the car if you want to get the most out of it. Is this correct? If so, how do I go about choosing the right size slick, what are the deciding factors?
For my street rubber I was planning on using 15x8.5 rim with a 265 tyre. So I have to find out what size slick will this allow and whether that measures up with the optimum slick as chosen from above.
Totally out of my depth here so any help would be great.
Cheers,
Liam.
#2
Posted 01 February 2006 - 09:16 PM
The diff ratio you want to use
Then calculate back the tyre size you need to achieve this
Then see if that height tyre is available and what size rim it suits
Then buy some wheels and get your diff done
#3 _LX406_
Posted 03 February 2006 - 07:00 PM
#4
Posted 03 February 2006 - 07:14 PM
#5 _MAWLER_
Posted 04 February 2006 - 05:37 PM
Taking the RPM and diff ratio what are the calculations that need to be done in order to come out with a tyre size?
Cheers,
#6 _CHOPPER_
Posted 04 February 2006 - 06:21 PM
#7 _MAWLER_
Posted 06 February 2006 - 04:14 PM
Does this mean I have to leave the purchase of rims and diff shortening till after I've done these two things?
Peace,
#8 _QIKSLR_
Posted 06 February 2006 - 05:37 PM
#9 _CHOPPER_
Posted 06 February 2006 - 06:09 PM
I deally, put the thing together with parts you have and chuck it down the 1/4. Provided you don't run out of revs before the end of the 1/4, the MPH figure you get will suffice. Work out what size tyres you want to run. The bigger they get the less cheap they become. If you manage to find out the revs you make maximum power, I can then post a RECOMMENDATION. Yes, it would just be a guide, but it should be better than just guessing.Thats a very kind offer Chop and would be awesome but I can't really post info on either account because I havn't had this engine dynoed past 4000rpm (only had about 800 k's on the clock) and have never run it down the strip.
Does this mean I have to leave the purchase of rims and diff shortening till after I've done these two things?
Peace,
#10 _jap-xu1_
Posted 06 February 2006 - 07:24 PM
a bigger diameter slick gives a smoother more controlled launh.Aren't you seriously better off tweaking the diff gears rather than slick size??
its best to go for the biggest diameter slick you can fit and then choose your diff ratio.
go here
http://www.speedworl...ex.com/calc.htm
and for metric imperial conversions go here
http://www.sciencema...onversions.html
#11 _MAWLER_
Posted 07 February 2006 - 04:46 PM
If I was to just choose a huge slick and rim then the relatively straight foward and cheap procedure might turn into major rear end work. Budget is tight at the moment and I can't afford to drop 3 g's instead of 1500 bucks.
What am I likely to be able to fit without moving suspension points or pumping the guards. I was already planning to make adjustments to the chassis rail at the rear of the tub.
What have ppl done, how much rubber are you running?
Cheers,
Ps. can someone explain the different measurements for drag slicks, I don't entirely understand what the figures are refering too.
#12 _jap-xu1_
Posted 07 February 2006 - 04:56 PM
28(tall)x10.5(wide)x15(rim size)
#13 _pro386_
Posted 07 February 2006 - 07:32 PM
#14 _355lxss_
Posted 08 February 2006 - 10:30 AM
I have a photo somewhere that i took of under the car when i stuffed the tires under the gaurds. I see if i can find it.
#15 _jap-xu1_
Posted 08 February 2006 - 10:51 AM
you can also get a bf goodrich and a yokohama tyre in that size which are made from much more street friendly compound that other brands
#16 _MAWLER_
Posted 08 February 2006 - 03:16 PM
#17 _355lxss_
Posted 08 February 2006 - 04:18 PM
Edited by 355lxss, 08 February 2006 - 04:20 PM.
#18 _355lxss_
Posted 09 February 2006 - 06:17 PM
You can see in the pic above the extra inch i'll gain from recessing the wheel well flush with the chassis.
Also measured up the tire from wall to wall which was 11in wide.
Edited by 355lxss, 09 February 2006 - 06:22 PM.
#19 _MAWLER_
Posted 10 February 2006 - 10:47 PM
Cheers,
#20 _QIKSLR_
Posted 11 February 2006 - 10:47 AM
I've got the same problem. I don't think the front end of the tub is an issue on sedans. My tyre is about 10mm from the shock.Thanks for the pics 355lxss. I was planning on trimming back to or even slightly moving the chassis rail at the rear of the tub as you have shown in the 2nd pic. I hadn't considered the inner wheel well at the front being an issue tho, I'm going to have to look at that as well and do some trimming to give the extra clearance to take out to the 275 region. How close is the tyre/rim to the shock, can you remember if we'll get away with it? I was hoping I wouldn't have to move the shock mounting points or trim the shock casing at all. Where you planning on having your diff shortened as well?
Cheers,
Heres some pics I took of a tubed non flared sedan. May be of use
Edited by QIKSLR, 11 February 2006 - 10:50 AM.
#21 _355lxss_
Posted 12 February 2006 - 10:50 AM
from memory the upper shocker mounting point isnt an issue but the bottom needs to be relocated on the inside of the original mounting position. Im getting the diff housing shortened around 4 1/2 inches in total.How close is the tyre/rim to the shock, can you remember if we'll get away with it? I was hoping I wouldn't have to move the shock mounting points or trim the shock casing at all. Where you planning on having your diff shortened as well?
#22 _MAWLER_
Posted 12 February 2006 - 12:23 PM
The only thing those pics do for me QIKSLR is to make me jealous!! Mini tubs, coilovers and panhard bar, or is it watts linkage, I can never remember which one is which
So looks like not going to be able to get away with it without moving the shock mount point, at least on the diff, moving the chassis rail in towards the centre at the rear of the tub, possibly rimming the tub at the front and who knows about height clearance.
CHOPPER, what is the best diameter rim to fit a 275/60 tyre on?
Cheers,
#23 _CHOPPER_
Posted 12 February 2006 - 01:17 PM
CHOPPER, what is the best diameter rim to fit a 275/60 tyre on?
I personally would put a 15" tyre on a 15" rim. For straight line action, probably 8.5-9.0" wide and try 20-25 PSI. A tyre pyrometer would be the best way to determine optimum pressure. Ideally take 3 readings, centre, inner and outer of the tyre. When the temps are equal after a run, leave the pressure there. If you make suspension alterations, the pressure may need to be altered. If somebody has an alternate method, feel free to tell us.
#24 _MAWLER_
Posted 12 February 2006 - 02:02 PM
CHOPPER, what is the best diameter rim to fit a 275/60 tyre on?
I personally would put a 15" tyre on a 15" rim.
Yeah, sorry, my bad. I meant width naturally, as you have picked up.
Cheers,
#25 _CHOPPER_
Posted 12 February 2006 - 03:20 PM
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