robmar Posted September 13, 2002 Share Posted September 13, 2002 I am sure this has been done before but I am too lazy to search the archives what is the correct offset for wheels on caterhams? does it matter front and back and 6 or 7 inch? also how do I measure them? Rob (mightly pi55ed off *mad* ) Link to comment Share on other sites More sharing options...
robmar Posted September 13, 2002 Author Share Posted September 13, 2002 I think I have found what I am looking for here however still not clear how to measure them? Vanessa from KN says "from center line of wheel to bolting face of web" Is centre line the physical middle of the rim? rob Link to comment Share on other sites More sharing options...
rgrigsby Posted September 13, 2002 Share Posted September 13, 2002 Hmmm if you can make any sense of either of these diagrams it may help.... Click here or this one Click here Cheers Rob G www.SpeedySeven.com Link to comment Share on other sites More sharing options...
robmar Posted September 13, 2002 Author Share Posted September 13, 2002 cheers rob, I think the 2nd one makes more sense to me is itoffset or backspace I should worry about, or both? rob Link to comment Share on other sites More sharing options...
Bob_r Posted September 13, 2002 Share Posted September 13, 2002 anybody know if offsets are the same for live axle cars (Ital axle)? bob Blatting around Bucks Link to comment Share on other sites More sharing options...
SteveP Posted September 14, 2002 Share Posted September 14, 2002 Having been round and round this loop recently, I offer the following: Offset is the distance between the vertical centre of the hub and the mounting face of the rim itself. So if the mounting face of the rim is exactly aligned to the centre of the rim, then it has 0 offset. If on the other hand the mounting face is closer to the outside of the rim, this is a positive offset and if the mounting face is nearer to the inside of the rim, then this is a negative offset. I have a 1989 DeDion which has the older style Ford hubs and have just fitted 6 x 13 KN Minators all round, the wheels having 23mm of positive offset - the fronts fitted fine, the rears needed a 3mm spacer to clear the DeDion tube - I understand that the hubs fitted to later models (1991?+) are slightly wider and won't need this spacer Not sure on live axle cars, but the PCD of the wheel will certainly be different to the DeDion version. SteveP Link to comment Share on other sites More sharing options...
scooby dooby doo Posted September 14, 2002 Share Posted September 14, 2002 the reuqired offsets are I think 16mm for 6" wheels and 23mm for 7" wheels. (it might be 18mm for 6" wheels though) if you search you'll find the post where Rob Morris (or it might have been Vannessa Morris) told me. HOOPY R706KGU CYCLE WINGS AEROSCREEN K SERIES CUCUMBER Link to comment Share on other sites More sharing options...
robmar Posted September 14, 2002 Author Share Posted September 14, 2002 Hoopy - is it the same for front and back offsets? I know understand it all, but want to check! rob Link to comment Share on other sites More sharing options...
Rob Morris Posted September 14, 2002 Share Posted September 14, 2002 Good day! Off-sets are: 1) Identical for live and De-Dion axled cars 2) +23mm for 6" wheels 3) +18mm for 7" wheels PCD (pitch circle diameter) is different for live and De-Dion but I can't remeber the exact figures. Di-Dion's are Ford fitment and Live are Ital, however, during the last bulk buy I did fine a live axle car running Ford PCD! Hope this helps and if it's for a "bulk buy" then good luck because the fun has only just started.............! Hoopy, See you at Cadwell on the 20th, don't forget your licence! Rob M. 40th Anniversary Vauxhall Man www.slipstream-trackdays.co.uk Link to comment Share on other sites More sharing options...
scooby dooby doo Posted September 15, 2002 Share Posted September 15, 2002 I'll be there Rob ❗ 😬 HOOPY R706KGU CYCLE WINGS AEROSCREEN K SERIES CUCUMBER Link to comment Share on other sites More sharing options...
Rob Walker Posted September 15, 2002 Share Posted September 15, 2002 Rob, Offsets were researched when we were trying to put together the recent Ultralite Bulk purchase. Caterham and Mike Barnaby confrirmed that the 6" & 6.5" both had +18mm and the 8.5" +23mm. Now the tricky part is you can measure a dozen different wheels and get a different back depth on each. Backdepth is from the inner edge of the rim to the mounting flange and this is down to how the edge of the spun rim is finished. Also what you have to bear in mind is that as an example a 6" rim refers to the width of the tyre bead sealing faces and not the overall width of the rim which will be around 7" for a 6J wheel. Confused I hope not. Link to comment Share on other sites More sharing options...
Rob Walker Posted September 15, 2002 Share Posted September 15, 2002 Rob, THe other problem that we found was that a particular manufacturer who will remain nameless had his spun sections machined with a taper on the inner faces and these fouled the de dion ears. The MBR and SLR split rims have the necessary clearance in this area. Lastly its important that the hub mounting face can clear the rear brake calipers and a clearance is also necessary in that area. Link to comment Share on other sites More sharing options...
robmar Posted September 15, 2002 Author Share Posted September 15, 2002 rob & rob - thanks for the info, hopefully having everthing sorted out this thursday and see some of you at cadwell, hopefully with some correctly fitting wheels if not I will be going around on some rather illegal looking 32's rob Link to comment Share on other sites More sharing options...
Jason Plato Posted September 15, 2002 Share Posted September 15, 2002 Rob , I hope you resolve the problems with the wheels , just make sure that their intention is not to machine the wheel centers !!! Good luck in getting your problems resolved , look forward to seeing you on friday at Cadders 😬 cheers dave Link to comment Share on other sites More sharing options...
Brightonuk Posted July 23, 2019 Share Posted July 23, 2019 Sorry if this is a dumb question but I keep coming up with different numbers here are my superlite rims anyone know the offset?I came up with negative 35mm but me thinks I am wrong I got 250mm from the ground to the flange / 2 = 125mm160mm from the hub face to the flange 125 - 160 = >35mm Link to comment Share on other sites More sharing options...
Area Representative Richard Price Posted July 24, 2019 Area Representative Share Posted July 24, 2019 Whilst I haven't got any of these wheels, minus 35 sounds too far inset.I'd got in my mind that 8.5" MB's were around minus 24mm offset, and I've just measured a bare wheel, and actually measured minus 22mm.I recall, when I've run 215 tyres on 8.5" MB's, there is not much clearance for the wheel to be any further inset (particularly while in roll in a corner), so I think its unlikely that your wheels are -35 Link to comment Share on other sites More sharing options...
garybee Posted July 24, 2019 Share Posted July 24, 2019 I'm not sure what you mean by 'hub face to flange'. That would be 0 surely. Also, are you measuring with the tyre fitted and resting on the ground? If so have you taken account of the amount the wheel is raised by the tyre? Link to comment Share on other sites More sharing options...
Brightonuk Posted July 24, 2019 Share Posted July 24, 2019 Yep I am sure I am incorrectI used this Technique and come up with the >35mm The Hoosiers are outside the rim so yes that would most likely be causing an issue as wellWere these rims supplied by Caterham back in the day? If so I will reach out to them. Link to comment Share on other sites More sharing options...
aerobod - near CYYC Posted July 24, 2019 Share Posted July 24, 2019 Your measurement method is correct, as is the result, assuming the straight edge is across the rear flange and you are measuring 250mm through the wheel to the front flange. Offset (or inset in this case) is the distance from the mounting face to the centreline of the wheel. ET -35 can work on the Caterham, but the front wing stays and rear radius arms or Watts linkages will restrict the tyre width that can be fitted. ET -23 with the 8x13 rear and 6x13 front is a typical Caterham offset. Link to comment Share on other sites More sharing options...
Brightonuk Posted July 24, 2019 Share Posted July 24, 2019 ThanksThe only reason for this question is new rear CF fenders from Wassermann as they offer different widths he wanted to be certain I ordered the correct ones As coming from Germany I cant exactly return them if they are incorrect I am sure the ones I have fitted (KCD) are standard but I wanted to make sure. Thanks Everyone Link to comment Share on other sites More sharing options...
Leadership Team SLR No.77 Posted July 24, 2019 Leadership Team Share Posted July 24, 2019 Standard width arches are fine with SLR wheels which is what you have. Link to comment Share on other sites More sharing options...
Brightonuk Posted July 25, 2019 Share Posted July 25, 2019 As always Thanks Link to comment Share on other sites More sharing options...
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