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Thread: CSR wheel offset difference

  1. #1
    Join Date
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    Default CSR wheel offset difference

    Croc, this is mostly for you. Maybe new James member as well.

    I got my new to me set of anthracite 10 spoke from an R400.

    The fit seems off but I think I'm coming to terms that it's right.

    Somebody mentioned that they might be CSR wheels. I took the deep dive and looked into it.

    CSR had a different front and back. Front offset was listed as ET13 on the wheel but that doesn't reflect that Caterham machines down the face on these. Face should look vastly different by at least 1cm of machining

    All mine should be square 6in et13

    I honestly think its the tire profile bring so square that's making it stick out more than normal. Being a smaller thicker sidewall that doesn't flex vs the 13s.

    So to the CSR folk, can you confirm that this isn't a CSR wheel?

    Sent from my Pixel 3a XL using Tapatalk
    2001 Caterham Superlight R

  2. #2
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    I know your problem and it's not the one you think it is.

    So for the record, Caterham road CSR 15 inch wheels:
    - Fronts 7x15 marked ET13 but are machined to ET40 if you listen to Caterham or ET38 if you measure mine.
    - Rears are 9x15 and are marked ET30 or ET8 (just to keep you on your toes) but if you measure then you get ET30!

    CSR race wheels - will also fit a road CSR after rear brake modifications like mine:
    - Fronts 7.5x13 ET34
    - Rears 9.5x13 ET34

    or if you have the race suspension set up with different rear uprights then you can run the race 15 inch wheel package
    - Front 7x15 ET40
    - Rear 9x15 ET27

    If I go to the Caterham parts website I find your wheel with an ET13 offset.
    https://caterhamparts.co.uk/lightwei...nthracite.html

    So far so good.

    However, in around 2013 or maybe it was 2014, Caterham changed the upright to a AP one. So the wheels after that date changed offset to accommodate. So your wheel would not be centered under the wing which is exactly what you have.

    What people did was change wing stays. I am not an expert on Caterham wing stays but I have heard people talk about there are 6 or 7 different versions available. How you know which one is beyond me. Your friendly Caterham dealer needs to chime in on this one. So this is one option.

    Being cheap, my first suggestion would be to see if you can heat and rebend the wingstay to accommodate?

    A second suggestion would be to unbond the wing and move it along the stay asymmetrically and rebond - that wont work well for you since your car does not follow the normal silastic bonding method but instead has screws to hold the wings on. You could still do this and rebond but you would have to accept some holes on the carbon. Tape the holes with black tape then apply the silastic.
    Last edited by Croc; 05-21-2020 at 01:39 PM.
    Mike
    2010 Caterham CSR with Cosworth 2.3 Duratec
    2018 Caterham 420R with 2L Duratec 210hp at Donington UK
    1975 BMW CSL Group 4 (restoration - engine and dry sump install time)
    1977 Holden Torana "A9X" (awaiting restoration)
    1985 Holden Commodore SS Group A
    1985 Holden Commodore Group A
    1982 Ferrari 400i
    1965 Ford Mustang Fastback "Holman Moody"
    1992 Ford Escort RS Cosworth WRC (fettling after long period of storage)
    1990 Range Rover 2 door Classic
    and another project car coming....

  3. #3
    Join Date
    May 2018
    Location
    Albany, NY
    Posts
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    Default

    Quote Originally Posted by Croc View Post
    I know your problem and it's not the one you think it is.

    So for the record, Caterham road CSR 15 inch wheels:
    - Fronts 7x15 marked ET13 but are machined to ET40 if you listen to Caterham or ET38 if you measure mine.
    - Rears are 9x15 and are marked ET30 or ET8 (just to keep you on your toes) but if you measure then you get ET30!

    CSR race wheels - will also fit a road CSR after rear brake modifications like mine:
    - Fronts 7.5x13 ET34
    - Rears 9.5x13 ET34

    or if you have the race suspension set up with different rear uprights then you can run the race 15 inch wheel package
    - Front 7x15 ET40
    - Rear 9x15 ET27

    If I go to the Caterham parts website I find your wheel with an ET13 offset.
    https://caterhamparts.co.uk/lightwei...nthracite.html

    So far so good.

    However, in around 2013 or maybe it was 2014, Caterham changed the upright to a AP one. So the wheels after that date changed offset to accommodate. So your wheel would not be centered under the wing which is exactly what you have.

    What people did was change wing stays. I am not an expert on Caterham wing stays but I have heard people talk about there are 6 or 7 different versions available. How you know which one is beyond me. Your friendly Caterham dealer needs to chime in on this one. So this is one option.

    Being cheap, my first suggestion would be to see if you can heat and rebend the wingstay to accommodate?

    A second suggestion would be to unbond the wing and move it along the stay asymmetrically and rebond - that wont work well for you since your car does not follow the normal silastic bonding method but instead has screws to hold the wings on. You could still do this and rebond but you would have to accept some holes on the carbon. Tape the holes with black tape then apply the silastic.
    Thank you Croc! You gave me far more information that I could have hoped for.

    I do believe I have the regular wheels and not the ones that are machined for CSR, everything leads to that. If they were CSR and machined they should have sat more sunken not poking out.

    I think you're right about wingstays. I dont have one to compare on hand but mine were never matching side to side to begin with. There has been some kind of impact or other (sitting on them??) difference between how the two sat.

    As far as maneuvering the fenders over, no luck even without the bolts. I'm in the process of remounting the set I have with BIGHEAD fasteners (the ones I had that didn't hold up on track day) but they sit in the same location. The lip of the fender is all the way against the vertical part of the fender mount, IE "max towards out" setting/location.

    After I get new mounts I could take another look at the side to side mounting of the existing one and see where the difference is.

    Edit: and yes mine are stamped ET13
    2001 Caterham Superlight R

  4. #4
    Join Date
    May 2020
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    Default

    Croc's summary is super-helpful. I knew about the offsets not being the same as the info that is cast into the rims on the road wheels but the other information is new to me. Thanks!

    Over here (in the UK) we get a lot of people advertising 15" rims as CSR wheels when, in reality, they are simply Caterham's 'standard' 15-inch 10-spokers. And actually finding any pukka CSR wheel sets to buy is off the scale in terms of challenge.

    James

  5. #5
    Join Date
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    You really cannot buy CSR wheels off the shelf anymore. You have to get them custom made which is not the cheapest approach to life.
    Mike
    2010 Caterham CSR with Cosworth 2.3 Duratec
    2018 Caterham 420R with 2L Duratec 210hp at Donington UK
    1975 BMW CSL Group 4 (restoration - engine and dry sump install time)
    1977 Holden Torana "A9X" (awaiting restoration)
    1985 Holden Commodore SS Group A
    1985 Holden Commodore Group A
    1982 Ferrari 400i
    1965 Ford Mustang Fastback "Holman Moody"
    1992 Ford Escort RS Cosworth WRC (fettling after long period of storage)
    1990 Range Rover 2 door Classic
    and another project car coming....

  6. #6
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    The Frozen Northeast
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    Quote Originally Posted by Croc View Post
    You have to get them custom made which is not the cheapest approach to life.
    Have you looked into having a fabricator just make a set of wingstays to match all the other bespoke parts of your car?

  7. #7
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    Seattle-ish
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    Given the difference in offset, any concern about changes to the scrub radius negatively impacting handling? It's not a huge amount, so probably not a big deal, but given the Caterham's best feature is arguably the front end, might be worth considering.

    -John
    '95 Westfield SEiW w/2.0L Duratec
    '68 Lotus Elan FHC
    '91 Miata w/Flyin Miata suspension & brakes
    '95 Porsche 993 C2
    '86 Porsche 944 turbo (neglected project car)
    Throttle Steer

  8. #8
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    Quote Originally Posted by wemtd View Post
    Have you looked into having a fabricator just make a set of wingstays to match all the other bespoke parts of your car?
    Its Vlad that has the issue not me. I am perfect! (just ignore my other bespoking elsewhere...)


    Quote Originally Posted by JohnCh View Post
    Given the difference in offset, any concern about changes to the scrub radius negatively impacting handling? It's not a huge amount, so probably not a big deal, but given the Caterham's best feature is arguably the front end, might be worth considering.
    Its a pretty small amount and besides its Vlad thats driving. Paige, his F, significant other, better driver, etc., is faster than him at lapping race circuits.
    She might notice it if I was driving.
    Mike
    2010 Caterham CSR with Cosworth 2.3 Duratec
    2018 Caterham 420R with 2L Duratec 210hp at Donington UK
    1975 BMW CSL Group 4 (restoration - engine and dry sump install time)
    1977 Holden Torana "A9X" (awaiting restoration)
    1985 Holden Commodore SS Group A
    1985 Holden Commodore Group A
    1982 Ferrari 400i
    1965 Ford Mustang Fastback "Holman Moody"
    1992 Ford Escort RS Cosworth WRC (fettling after long period of storage)
    1990 Range Rover 2 door Classic
    and another project car coming....

  9. #9
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    Seattle-ish
    Posts
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    Good point Mike, I forgot to account for the Vlad factor. Never mind

    -John
    '95 Westfield SEiW w/2.0L Duratec
    '68 Lotus Elan FHC
    '91 Miata w/Flyin Miata suspension & brakes
    '95 Porsche 993 C2
    '86 Porsche 944 turbo (neglected project car)
    Throttle Steer

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