So why would I be starting this topic? I don't build 70s cars (and I'm not even supposed to like them, but that is starting to change)
Answer: I thought I'd check whether there is a need/desire for more options for the wider 13" wheels that 70s F1 cars used. This follows from the Hesketh post.
Chris and Martin have determined what size inserts need to be crafted for Martin's Hesketh, but is there a 'need' for wider wheels of a different or 'improved' design?
RS Slotracing makes a 13" by 5mm and a 13" by 7mm, both with double flanges. (These would work for some 1963-5 half tonners and perhaps as front wheels on some 70s F1 cars)
Ranch Design and BWA have 13" wheels in 3 different widths, but I believe that the current maximum width offering from both suppliers is 9mm. (Please correct me if I'm wrong). The 13" wheels that I have from Al and Steve have double flanges.
BWA has quite a few offerings of wider wheels in 15" diameter of course.
Penelope Pitlane offers wider wheels but with big hubs.
I'm missing somebody I'm sure, but I'll close:
1) Do folks need/want 13" 'hubless' rear wheels that are 12mm, 13mm, 15mm (or more) in width? 2) With a double flange or with the center rib?
Last Edit: Jun 20, 2012 9:30:19 GMT -5 by Mark Huber
Post by Andrew Rowland on Jun 20, 2012 11:37:03 GMT -5
Oh Mark, you beat me to it!! What follows is my fairly strong view. I would love to start a discussion here so that everyone else's experience was also brought to bear on this oh so important issue. I can draw up anything anyone wants and send it in CAD format ready for CADCAM as required although anyone int he business would do that anyway.
So in my view there is a BIG need for these wheels. The fact in my view is that with these '70's cars the wide wheel and particularly tyre combination adds a huge amount of weight to the car and especially since they are 'unsprung' and rotational they have a huge affect on performance. That is why Russell as one example was talking about Slot.it hubs and NSR tyres as he knows they are by far and the best combination as they weigh NOTHING.
This is all less important for all you '60's and '70's guys since the tyres are so narrow they don't represent a huge amount of overall or rotational weight.....
In my personal view the best current wheel tyre combo is Ostorero since at least they are to scale. The tyres once run in to true them are soft enough BUT both the hub and the tyre are SO HEAVY.
So the question is not if a wheel is required (Martin's question proves it is) but how we design it and for what tyres.
Now the Slot.it combo (with slot.it or NSR tyres) are fine up to 1970 (and some teams in 1971) since Firestone were playing with low profile tyres so the slightly larger rim with the width of tyre they produce look and go fine, but from there we need the really meaty tyres which can take us pretty much all the way to the end of the '70's. (Ignoring small differences here.)
In my view though we have a real problem because designing and turning up the wheels is 'easy' but which tyres will we put on them? I know Ortmann are 'standard issue' particularly in the UK but in my experience they are so far out of true that one loses at least 2mm off the diameter truing them and then the diameter isn't right! Plus the inside edge looks 'a little rough'. I think they may be fine for all those '50's and '60's cars as they need to be worked on anyway but the wider tyres are just not good enough - not when compared to things like NSR and Slot.it.
Much modern class racing 'give out' a set of tyres at the start to make sure that there is an even playing field so things like Ortmann just couldn't work.
My view is to make a wheel that fits the Ostorero tyre for now (accepting the weight penalty of the tyre) but with the idea to eventually make a second version WITH a NEW TYRE (who and how I don't know) using the modern 'air system' in order to keep rotational weight down to an absolute minimum.
This is not that far fetched given that to get my Tecno project off the ground i'm going to have to tackle this anyway.
Final point - all wheels should have a recess also on the inner hub side so that joints etc. can be hidden inside as per the real cars..... Why don't the big manufacturers do that?
Post by Chris Wright on Jun 20, 2012 11:55:00 GMT -5
Looking down the road, and adding a voice of practicality, when it comes to future race series for 1970's cars, people will want a choice of rear tyres. Ortmans, and Paul Guage tyres already exist for the rears in appropriate sizes, and I'm willing to bet they'll out-perform Ostorero's.
The Ostorero tyre could prove problematic. Electric Dreams is out of them, and at the best of times Ostorero products can be hard to get Stateside etc.
Racers will want the best compound (just like their full-size counterparts), they'll go for Ortmans etc, or whoever has the best compound. They'll compromise on wheels.
So....if you can design a state of the art wheel that will accept a clone of the Scalex M23 mcLaren tyre, and accept a 365" insert (because there are allready 30 different inserts available to this size from BWA RS etc) you'll have it made.
Now I know you're rivet counter just like me, but Mr. Practicality don't care.
Now there's also the question about the front's?
PS Most 1970's F-1 cars will go to Proxy races, or Wolves etc, there won't be a "give out tyre", the tyres used in these races are glued to the wheels and trued up. It's an extremely competitive arena, and makes a huge difference in the performance of most cars. Your solution on the right looks great by the way, now if you could only get NSR Ultra's in that size!
Many thanks; I will investigate asap. Front wheels for the P34 seem to be a perennial problem. The 6-wheeled Tyrrell isn't quite my cuppa, but I have a couple of chums who appear to be incapable of leading a meaningful life without 'em. A lexan body from Betta and Classic is readily available, along with all the usual bits and pieces, but 'those' infernal wheels and tyres...
Perhaps this is a gap in the slot market that someone with a lathe could possible fill.