Anti Roll Bars

PostPost by: gav » Mon Jan 06, 2014 9:17 pm

Hi all

Where might I find a good, really firm anti roll (sway) bar to use for sharp bends in hills and sprints. I want to flatten out the turn in and smooth the run out.

Also, what is the best type of bushing to use (this is a road car as well as competition so I don't want to rattle home afterwards).

Many thanks
Gavin
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PostPost by: gino1 » Tue Jan 07, 2014 8:38 am

Hi Gavin,

I've already bought a couple of front anti roll bars from Pat Thomas at Kelvedon.
They really stiffen up the front end and no more leaning over in sharp bends :wink:
They come complete with the links too and do not rattle in time.

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PostPost by: nomad » Thu Jan 09, 2014 3:00 pm

gino1 wrote:Hi Gavin,

I've already bought a couple of front anti roll bars from Pat Thomas at Kelvedon.
They really stiffen up the front end and no more leaning over in sharp bends :wink:
They come complete with the links too and do not rattle in time.

Gino
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Can someone please tell me the diameter of Kelvedon's " sway" ( US! :D )bar. 7/8 inch seems to be common and I think I would like to go heavier.

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PostPost by: rgh0 » Thu Jan 09, 2014 9:36 pm

I would personally not go heavier than 7/8th inch (e.g. to 1 inch) unless you a building a really stiff track only car with maybe 300 lb/in front springs and 200 lb/in rears. I have also heard reports of the much stiffer 1 inch bars breaking off the shocker end studs also and people recommending doing mods to have a drop link at the end of the bar.connecting to the suspension rather than the standard arrangement.

cheers
Rohan
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PostPost by: Mazzini » Thu Jan 09, 2014 10:38 pm

rgh0 wrote:I would personally not go heavier than 7/8th inch (e.g. to 1 inch) unless you a building a really stiff track only car with maybe 300 lb/in front springs and 200 lb/in rears. I have also heard reports of the much stiffer 1 inch bars breaking off the shocker end studs also and people recommending doing mods to have a drop link at the end of the bar.connecting to the suspension rather than the standard arrangement.

cheers
Rohan


Dear Rohan,
Whom would you recommend? TTR's ARB is 13/16th, Spyder's is about standard and I haven't heard back from Kelvedon yet, though Gino seems to be very happy with Pat's product.
Thanks,
Rob
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PostPost by: rgh0 » Fri Jan 10, 2014 1:20 am

Hi Rob
What you use really depends on the rest of the car suspension and tyres and the cars intended use. Tell me some more and I can give some guidance at least based on what I have tried over the years. In the end suspension setup and handling is a personal preference thing to a large degree and there are no absolutely right answers ( though there are a few absolutely wrong ones !!!)

cheers
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PostPost by: Tahoe » Fri Jan 10, 2014 4:06 am

Not to take over this thread but I have a question. I purchased a used 7/8 bar (ADDCO) a few months ago. I have a very early Spyder suspension (made first 2 years) with inboard (short) Koni's in the rear and Koni's in the front. Not sure of the spring rates. The reason why I bought the 7/8 bar was because of lots of oversteer while driving. So I get the bar it looks great, but I need bushing for the drop links. Jeff at JAE suggested +2 bushings. What are people doing for these bushings? Is it as easy as replacing the bushing to fit a 7/8 bar or would it be better to replace the drop links to something available, or make a custom link? I have the car down for the Winter, but want to get it on the car ASAP because of planned road trips in early Spring. I'll wait to see if there are any answers, but if not the old bar comes off next week and I'll figure it out.
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PostPost by: rgh0 » Fri Jan 10, 2014 5:16 am

If you cant locate a link to suit a 7/8 inch bar from any of the usual Lotus suppliers ( I think it has been mentioned Kelvedon supply them to match their 7/8 inch bar). Find a suspension place to source a suitable clamp on bush and link and cut and weld it to the original lotus link upper end - that is what I did. You just need be careful when positioning the new links to ensure they don't hit the chassis cross member as the suspension moves over its full travel.

Picture of my links

split roll bar link 1.JPG and

split roll bar link 2.JPG and


cheers
Rohan
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PostPost by: Mazzini » Fri Jan 10, 2014 8:32 am

rgh0 wrote:Hi Rob
What you use really depends on the rest of the car suspension and tyres and the cars intended use. Tell me some more and I can give some guidance at least based on what I have tried over the years. In the end suspension setup and handling is a personal preference thing to a large degree and there are no absolutely right answers ( though there are a few absolutely wrong ones !!!)

cheers
Rohan


Dear Rohan,
I have TTR fast road shocks and springs all round, original bump stops and will run 4mm toe in front and rear. 155 x 13 tyres. Waddya reckon?
Thanks,
Rob
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PostPost by: rgh0 » Fri Jan 10, 2014 10:25 am

Do you know the spring rates for the TTR fast road springs. I would suspect they will be maybe around 25% stiffer than standard. A 7/8 inch bar will be good with that set up. I had something similar early on with my Elan when I was still running 155x 13 Michelin XAS FF. I personally would not use anything bigger. I personally would also fit a space under the rear Aeon rubber springs ( aka bump stops) with an approx 30 mm plastic spacer sitting on top of the shock ( this assume standard ride height for the rear suspension. This stops the car sitting down on its outside rear wheel and lifting its inside front wheel with the stiffer roll bar. It also stops the Aeon spring getting worn by the top of the shock tube which will happen if you use this setup to its full extent

If TTR recommend a 13/16th bar with their fast road springs you could try that first as they know what they are talking about generally. Bars are not that expensive and you could go to 7/8th if your personal taste is for something stiffer

cheers
Rohan
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PostPost by: nomad » Fri Jan 10, 2014 2:51 pm

I'm sure I have it somewhere but haven't a clue where. Can someone tell me the stock spring rates for the S1??

Rohan, I am planning on running rates about 20% stiffer than stock as Steve ( bitsobrits) has recommended to me . (We both drive the same kind of roads :D ) I appreciate your info and pic's of your bar mount. I have made up bar mounts for sprites out of a piece of moly filled poly carb that work well and planned on the same for the Elan. Soliding up the bar to frame mount would help on body roll I would think. Just mentioning that moly filled poly carb or nylon works well in this app.

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PostPost by: cabc26b » Fri Jan 10, 2014 3:32 pm

For my duel purpose exercise I used a NOS 7/8' adco i saw on ebay. Front is set up with With TTR shocks and 250lbs springs, 175/70 13 Sumitomo tires/tyres. Adapted the original mounts with a clamp and custom bushing. I would use something other than rubber on the ends though ( will replace someday) picture attached.

Full race was 1" solid mounts , 300LBs + springs rod ends everywhere and Avon ACB10 7x22x13"

IMO 7/8 is more than you need, but like Russ i already had on the shelf when it came time to build so i put it on.

George
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PostPost by: Mazzini » Fri Jan 10, 2014 11:30 pm

rgh0 wrote:Do you know the spring rates for the TTR fast road springs. I would suspect they will be maybe around 25% stiffer than standard. A 7/8 inch bar will be good with that set up. I had something similar early on with my Elan when I was still running 155x 13 Michelin XAS FF. I personally would not use anything bigger. I personally would also fit a space under the rear Aeon rubber springs ( aka bump stops) with an approx 30 mm plastic spacer sitting on top of the shock ( this assume standard ride height for the rear suspension. This stops the car sitting down on its outside rear wheel and lifting its inside front wheel with the stiffer roll bar. It also stops the Aeon spring getting worn by the top of the shock tube which will happen if you use this setup to its full extent

If TTR recommend a 13/16th bar with their fast road springs you could try that first as they know what they are talking about generally. Bars are not that expensive and you could go to 7/8th if your personal taste is for something stiffer

cheers
Rohan


No sadly I don't know the spring rates for TTR's fast road springs. What did you make of the XAS FF's? I think it's the route I'm going to go down. I've used another form of bump stop as the spacer for the Aeon spring, the type that can be cut down to size, probably a bit more compressible than a plastic spacer...ah well its all bolted up now. I'll try the TTR offering to start with.

Many thanks for all your advice - lapping the hubs worked a treat :D
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PostPost by: rgh0 » Sat Jan 11, 2014 12:57 am

The XAS FF were a great tire especially on the road. This was many years ago and they were one of the first 'track day' tires with a soft compound in road legal construction you could get. The modern tyres such a the 175/60 x 13 Yoko A048R I use now are far superior but for a traditional profile tire on an Elan the XAS FF is great if you don't do a lot of miles as the cost is high and the wear rate high also :D

The Dave Bean Spring Rates and bars are versus standard as follows:

Standard - 0.688 inch bar and 75 lb/in Front , 68 lb/in Rear spring rates.
High performance road - 0.750 inch bar ( you can use standard plus 2 bushes) and 115 lb/in Front and 95 ln/in Rear ( I tried these but ended up with a 7/8th bar when the car was still regularly used on the road still)
Road race - 1 inch bar and 160 lb/in Front and 125lb/in Rear ( I use these rates but with a 7/8th bar for my Elan these days as it is basically a track only car, you can use them on the road but it does get a bit harsh!)

TTR's fast road spring rates will be similar to the DB high performance road and a 13/16th inch bar from TTR or 3/4 inch bar from DB is getting down to personal preference. I ended up with a 7/8th bar when the car was still set up for the road as well a sprints and hill climbs as in this situation I personally prefer a car a little softer on the springs but with a stiffer front roll bar given the state of our roads and tracks here in Australia.

cheers
Rohan
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PostPost by: nomad » Sat Jan 11, 2014 5:34 am

Interesting stuff, Rohan. I guess i was assuming that since the radius of the lever the bar makes from frame to shock is as long as it is that one would want a stiffer bar. Guess I'm comparing to Sprites. But then the attachment point on the lower A arm is something I am not taking into account and i imagine that would make a difference.

Thanks much for the info.

Kurt.
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