Richard Price

Yes, I'd like a garage space please... (If I request a garage space, its bound to be warm and dry! :-) )

'Anyone who was thinking of entering but hasn't yet, needs to hurry up! I've just spoke with Gavin Leadbetter who tells me that the events are now almost full with just seven places remaining!

Paul, That is correct. As there is a return road, the second runner normally runs very soon after the first runner.

Loton and Prescott are likely to fill up quickly too.

Rex, 205/45-16 and 185/70-13 are pretty much the same in overall diameter. Both sizes of 13" ZZS are significantly smaller in diameter. Don't forget that any change of camber will also affect the toe, so both need to be adjusted together. No, not really. There is quite a bit of scope for ride height adjustment to accomodate different wheel sizes.

No, I don't think so :-( The front is the greatest concern.... The 16" tyres have a nominal diameter of 590mm, and the 185/55-13 fronts have a nominal diameter of 533mm, which would drop your ride height by around 28mm. If the spring platforms are simply adjusted to correct the ride height, the camber and toe are likely to be quite some way away from optimum. Typically, increasing ride height is likely to reduce negative camber. Assuming the camber setting did stay acceptable, the toe measurment is likely to have changed due to the bump steer characteristics. At the back you'll loose around 12mm, but spring platform height should easily correct that.

Shaun, I'll confirm Dan's comments. They don't work that well from cold, so a smaller tyre, worked hard from the start, gets better as the run progresses. If you go too wide, you may never get them warm enough to work.... The 215's are larger diameter than Kumho 215's , so you would also need to drastically rework your front wings and stays. They're also around 20mm larger in diameter than 215 Kumhos, so, to run at the same ride height, you'd need to use up some of your bump travel. How much bump travel do you currently have before the bump stops? Wide, cold ZZR's on a damp track..... No thanks :-)

Each turn of the top ball joint is roughly 0.25°.

Longy, Most folks are using 185/60-13 A539's. They're classed as a standard road tyre, so available in just a single compound. However, do you really need to buy a second set of wheels and tyres? What tyres do you currently have on your 14" wheels? There is far more to be gained from learning how to approach competition, learning the courses, and learning to drive the car on these courses, than there is between different tyres. (when running standard road tyres, I've run on 14, 13, and 15" tyres respectively, and would say that, in reality, there was very little difference between any. However, during that time, my own ability changed dramatically!)

Beagler, Are HiSpec aware of the differences between pre and post 2014 Caterhams with Lug and radial mounts respectively?

My 2002 car has just four dip switches, but there are actually only two settings. When I originally swapped from 185/60-14 tyres to 185/60-13's, I found that the Speedo was over reading irrespective of how the dip switches were set :-( I ended up swapping the speedo drive gear to get a reasonably accurate speedo reading. (But, that was around eighteen years ago, so I don't remember the detail.

Dave, 'sorry, I guess we should have clarified what year of chassis you need these bolts for. What year is your chassis? The special bolts l linked to are to suit Imperial chassis (S3 and SV, 2006 and earlier, and all CSR's).

Dave, Beware! These are not simply "65mm x 12mm bolt", the are specials, and described as "M12 X 65MM WITH 1/2" SHANK" https://caterhamparts.co.uk/bolts/1465-bolt-m12-x-65mm-with-1-2-shank.html?search_query=79046&results=1

Yes. Plenty. I did a 2d drawing a couple of days ago, which only took a few minutes to do. Once you have a CAD file, what do you want to do with it? I'm happy to share it (but anyone that can read a .dwg file, is also likely to be able to create he file as quickly as I did.) I think the profile of the teeth is really not that critical to a few tenths of a mm. As I've said before, if replacing one of these rings, I'd really go with a smaller number of larger teeth, and use a sensor with a greater sensing range and tolerance to adjustment.

Anker, This link gives a little detail for Sierra driveshafts:- http://www.locostbuilders.co.uk/viewthread.php?tid=182291 I suspect you have a little more to look at rather than simply repairing the inboard CV joint..... It's very likely that inboard CV joint failure is a result of another issue. I suspect you may also have a problem with either suspension (which has allowed abnormal driveshaft articulation), or, spring failure in the outer CV (both CV's have springs that centralise the driveshaft between the two CV's. If the spring has failed in the outer end, that may allow the inboard end to come out of its pot). Unfortunately, I think the parts to repair the original Ford Sierra shafts are long obsolete. The later complete shaft is a like for like replacement:- https://caterhamparts.co.uk/driveshafts/7039-driveshaft-s3-lh-ford-differential.html

Anker, your driveshafts are of an earlier style than those in the linked rebuild article. your shafts use Ford Sierra CV joints, and special shorter shafts. The later shafts (as shown in the article) are a bespoke Caterham part made by GKN.

David, the tyres I used to set a new class record at Loton this year were three and four years old. The oldest we're still good enough to sell on as legal road tyres! I bought a new set mid season, but I wouldn't say they are noticeably different in performance to the old set.

David, The 13" road legal (list 1b) ZZS's are product codes 7718 and 7719 for the 185 and 215 sizes. See here:-https://caterhamparts.co.uk/98-zzs The EU labels can be seen on the links from the chart at the bottom of this page here :- https://www.avontyres.com/en-gb/tyres/zzs?cartype=motorsport

Is the number of teeth actually that critical? I would suggest that it is not. A few years ago, a friend's speedo was not working. We found that the gearbox driven sender was actually OK, but was not being driven by the gearbox. The quill was OK, as was the plastic driven gear, but the driven gear was not engaged with the worm gear on the gearbox output shaft. Rather than removing the engine and 'box to rectify the root cause, I fabricated a bracket to mount a proximity detector to count diff input drive flange bolts (actually, every other bolt, as the four bolts are not equidistant), and wired to the original wiring. Then, with a little trial and error, the speedo was recalibrated to read accurately. The speedo action was normal despite only around 8 counts per wheel rev. I feel like there are frequent posts about problems with speedo readings, either due to flex of the bracket, failed or out of adjustment sensors, or damaged wiring. I would suggest that a redesign could massively reduce these issues. The sensors seem way too sensitive to adjustment to me. I would go with a larger diameter sensor, with a greater sensing range, mounted on a bracket from the diff, and use a toothed ring on the inboard end of the drive shaft with a much reduced tooth count. Whilst not to drive a speedo, We're using a similar setup on my sons hillclimb car (for traction and launch control). Our sensors count 16 teeth, and still work effectively over a range of adjustment of over 1mm. I would not worry about having to shrink fit rings to drive shafts. I would secure the rings to the drive shaft with three roughly equally spaced grub screws. For reference, I knocked up a rough CAD drawing and got some quotes from https://www.fractory.com/ Eight rings laser cut from 10mm steel plate, woud cost about £90 (where any order less than eight still cost around £90). Twenty rings would cost about £120, and 40 around £175.

ZZS's are available in a compound (RT7) specifically for race use in wet weather. However, the Avon suggest that the RT7 compound is list 1c rather than the required list 1b for class 3. There is actually a misprint in the 2021 blue book. It lists "ZZR RT7" in list 1c, and should read "ZZS RT7".

Whilst I don't see the need to remove the plate, if you do want to use to nut it want to avoid the issue of the plate not sitting flush, then use countersunk to nuts. https://www.ebay.co.uk/itm/RIVNUTS-THIN-SHEET-RIVET-NUTS-COUNTERSUNK-STEEL-THREADED-INSERTS-M4-M5-M6-M8-M10-/182064840166?mkcid=16&mkevt=1&_trksid=p2349624.m46890.l6249&mkrid=710-127635-2958-0

I'm pretty sure there is a significant advantage for the second driver of any car that is dual driven, particularly when using the current generation of list 1b tyres without pre start tyre warming. Additionally, the shorter the time between these runs, the greater that advantage is. I fully support the proposed change.

I agree with Simon ( yes, I know that's unusual ). I don't think electrically adjustable suspension will offer any performance advantage for speed events. If it did, we would have seen all the top cars in the British hillclimb championship using it! (which they are not!)

Yes, I think these are appropriate changes to simplify and clarify the championship regulations. However, there is a line in section 3.3 the 2021 regulations that reads:- As all other modifications are free, that line seems to be redundant. On the subject of "driver aids", I suggest specifying "traction control", "Launch control", and "flat shift" (to cover either manual change with shift cut or and integrated paddle shift system), as specific "driver aids"