03-26-2014, 02:50 PM | #23 |
Enlisted Member
2
Rep 45
Posts |
|
Appreciate
0
|
03-27-2014, 09:10 AM | #24 | |
Major
450
Rep 1,358
Posts |
Quote:
If your looking for the ideal track setup for DEs I recommend 18s w/275s all around or 285 square with camber plates. If you're looking to competitively race the 1m on track I can't answer to that. I've never driven a 1m with full cage and proper race suspension. My gut instinct is probably wider in the rear than the front. |
|
Appreciate
0
|
03-27-2014, 09:12 AM | #25 | |
Banned
1130
Rep 4,686
Posts
Drives: L'Orange
Join Date: Jul 2013
Location: Brooklyn, NYC
|
Quote:
|
|
Appreciate
0
|
03-27-2014, 05:08 PM | #26 | |
Enlisted Member
2
Rep 45
Posts |
Quote:
Adding 4-5lbs to each corner with big tires will make your car slower and probably have less/same traction |
|
Appreciate
0
|
03-27-2014, 06:09 PM | #27 |
Major
450
Rep 1,358
Posts |
From experience I have to disagree with both of you. My experience comes from driving and/or instructing half a dozen different 1ms on the track with various tire setups. Also my experience comes from 13 years of instructing and 12 years wheel to wheel racing.
|
Appreciate
0
|
03-27-2014, 06:50 PM | #28 |
Captain
118
Rep 898
Posts
Drives: '69 GT3, GT4, 1M, 912
Join Date: Nov 2010
Location: SF Bay Area, Shenzhen, Oman
|
While there are rare cases when wider isn't faster, and even rarer cases when it's not grippier, they are in my opinion clearly the exception not the rule in our size and weight class. I generally prefer to drive on skinnier tires, and maintain the stock widths on my 1M for that reason (even going down to 18s much of the time to increase slip angle using OEM M3 wheels). However I do believe that wider would be quicker against the clock in nearly all cases, and have a fair bit of experience that proves that out. Consider that vipers run 335s with significantly less weight on them- no issues making them work.
It does depend on the type of tire, if the suspension geometry can hold the tire flat, etc, so it can get tricky. Put a 305 30 19 on a very light old 911, as I have, and you'll recognize that many variables in the cars suspension need to change in order to make the tire work. However that's going from something made for 175 70 15 bias plys to a tire that the designers wouldn't even recognize. In a 1M's tire, power and weight class it's much simpler. I have a suspension analysis program that includes various tire models. They are generalized rather than specific, but they give a good point of reference. Going from a 265 to a 285 gives a slight but noticeable measurable increase in grip at out loadings, and importantly that grip comes at a quite a bit lower slip angle, so you get faster response. On a big track as robertm is referring to this will be compounded because you'll be less likely to overheat the compound, increasing grip further. In the wet skinnier than we run is better. I'll argue that on the street usable feedback from the tire and slip angle is more important than width. For these reasons I like and personally recommend not going wider than stock on the street. But against the clock I agree that it's slower, even with the increased weight. For reference, I've got cars that I compete with wearing 175 15s through 315 17s and 305 19s, with lots of stuff in between. The 175s bring some of the biggest smiles.
__________________
1M, GT4, 1969 Porsche 911 w/ 997 GT3 Cup Motor (435hp & 2,100 lbs)
|
Appreciate
0
|
04-14-2014, 04:02 PM | #29 | |
Moderator
29134
Rep 13,076
Posts |
Quote:
__________________
///M is art ↔ Artemis
|
|
Appreciate
0
|
04-14-2014, 09:47 PM | #30 | |
First Lieutenant
55
Rep 348
Posts |
Quote:
|
|
Appreciate
0
|
04-15-2014, 11:01 AM | #31 |
Colonel
381
Rep 2,926
Posts
Drives: Cayman GT4, 135i
Join Date: Apr 2008
Location: NJ
|
FWIW - On Apex ET22 My Front end 1M conversion Rubbed with 265 PSS on low speeds in parking lots. I switched to 255s to eliminate it.
__________________
Current: M2CS
Gone but not forgotten: Cayman GT4, M2C, 2011 135i, E83 X3 6MT, 2016 SO M3, 2012 335iS, 2010 135i and 2006 e90 325xi |
Appreciate
0
|
04-16-2014, 01:43 PM | #32 | ||
Banned
7905
Rep 11,785
Posts |
Quote:
if you are speaking from Theory... then that is fine.. but from an EXPERIENTAL (no.. that's not a made up word..) perspective.. I think you are incorrect. The " optimal traction footprint" for the 1M is likely acheived with wider tires.. PARTICULARLY in the rear. please do not ASSUME (that others are drivers " obssessed with tire width" ) I am not obsessed with tire width and nor is Robert... having both run 15s on our E30M3s for years. Like Petevb.... I would prefer to run smaller tires... First off.. they are cheaper... Second .. they have less unsprung weight.. as you mentioned.. For a long time E30 M3 owner.... that last part is VERY important.. Quote:
The 1M does NOT lack power. it LAUGHS at a few additional pounds of unsprung weight and says.... (scharzenegger voice) I got TORQUE baby.. get on my back and LET's GO! make no mistake... I am not saying that the unsprung weight isnt a factor... of course it is... but this car is FAR less affected by a few pounds of unsprung weight than probably any BMW before it.... ( E30M3.. E36M3.. E46 M3..E9x.. Z3..Z4.. you name it.) harold of HPA motorsports has commented in the past as well that wider is better on the 1M... and IIRC he felt the best grip on the car would be with 10" wheels up front and 11" wheels in the rear. Personally. I didnt really subscribe to this either.. until I put 285s on the back of my car. Now... i concur. if I were racing and wanted to go FASTEST with respect to putting power the ground.. ... I would keep a staggered setup and go as big as possible in the rear. However.. I do feel that the car * handles* best with the least understeeer by using a SQUARE setup however... and i very much recommend that to others. The car turns in SO much better with a square setup with camber plates than it does stock or on a stock setup with wider front and rear tires that it's a night and day difference. Here locally in DFW we have about 16 owners with 1Ms... and about 4-5 of us all are close friends and have shared our cars with each other so we can feel different setups. Still not a believer? Grab a stopwatch and borrow some wheels and tires and let us know what you find from experience. Last edited by M3 Adjuster; 04-16-2014 at 02:21 PM.. |
||
Appreciate
0
|
04-16-2014, 05:14 PM | #34 | |
Brigadier General
115
Rep 3,070
Posts |
Quote:
As a relatively ordinary driver and with no chance of a good track around I feel that stock sizes or 255/275 sizes of good tires like PSS on stock wheels and camber plates dialed for 'more fun and agility' are all I need here. But should I go further and on track for fastest possible, not necessarily being more fun, than I would probably choose 18' wheels with a 265/285 or 285 square set up, semi slicks and more camber than I actually have. You can't put too wide of a tire at the rear of the 1M; 295s with stock 19s, 285 with most 18s and 305 or 315 with 10.5 or 11 inch wheels would definitely give quicker times. Just plain meaningless on essentially street/back road driven 1Ms imo because those are places where stock 1M's trade mark behaviour (of playfullness) should be preserved over 'grippier/quicker'.
__________________
"The mark of a great car is one whose overall competence exceeds what you should expect from its individual components and the 1M does just that", Chris Harris.
BMW 1M-SOLD-: TECH: Evolve Race+N55mids, Evolve IC, Michelin PSS, ER cp, aFe filter, CDVx, Vorshlag camber plates, BMS OCC EXTERIOR: trunk spoiler, blacklines, black grills, IND goodies INTERIOR: Alcantara steering wheel, steel pedals, custom mats, MPower e-brake. Last edited by ozinaldo; 04-16-2014 at 05:33 PM.. |
|
Appreciate
0
|
Post Reply |
Bookmarks |
Thread Tools | Search this Thread |
|
|