Ride height and measuring

[550superfast]

What ride heights are you all running and where are you measuring from/to?

I'm struggling to get lower that 140 and 158mm measuring between the wheels, from the ground to the chassis rail. Lotus previously measured at 136 / 130mm.

[alias23]

This is a hot topic right now for me.... Since moving to the Ohlins, it has become near impossible for me to get anywhere near the lower (and preferred) ride height that I had on the Nitrons. My car did look a little 4x4 compared to @GFWilliams earlier this week when we did a comparison. The rear does seem to have room to wind down, I could probably go another 10mm (I wound down 5mm last night). The fronts seem the problem, I only had 5mm left of wind down, this makes the spring very very loose (especially as no helper on the front) when unweighted (jacked up). Im also concerned if this leaves enough travel for the shock as to me it doesn't seem a lot left!

I'll get out later and try and do a measure to compare.

[Hangar 111]

140/158?!?  You are measuring it correctly?  That sounds higher than standard suspension (may well not be).  Should be measured at the front and side jacking points.

We are running around 120mm on our EX460 demo car, as we wanted to keep it sort of usable. On JRZs, of course

Hmmm you don't have alot of damper travel there!  Also if the springs are unseating on full droop, whilst not uncommon on some setups, that is not an ideal situation.  If you have compromised the damper travel with the spring platform adjustment, then I'd say you need to change the springs, which will also give you some more ride height adjustment.

Dave

Edited June 7, 2018 by Hangar 111

[Arun_D]

H111 got my TTX to 122mm at the front, keeping the rear set to the original 136mm, the act of the front coming down naturally brought the rear measurement point down to 133mm. This is with the front platforms wound out all the way on the fronts. With this comes the same issues as Imran describes above.

[550superfast]

I am measuring at points A and B

[Hangar 111]

That's correct.

Don't forget it should be done with weight in the car, fuel level, tyre pressures all set.  And a flat and level floor, of course!

Dave

Edited June 7, 2018 by Hangar 111

[550superfast]

Thanks - I was not in the car, so I guess I need to fill with fuel and put 80kg in the drivers seat. I can't imagine it coming down too much though. I'll check this tomorrow.

I'm in touch with Russ at Mick Gardner Racing who have just rebuilt my Ohlins about this - I'll post up what he says.

[550superfast]

1 hour ago, Arun_D said:

H111 got my TTX to 122mm at the front, keeping the rear set to the original 136mm, the act of the front coming down naturally brought the rear measurement point down to 133mm. This is with the front platforms wound out all the way on the fronts. With this comes the same issues as Imran describes above.

Are you springs loose when you jack the car up?

[alias23]

Just now, 550superfast said:

Are you springs loose when you jack the car up?

Mine are yes... loose but still in place at the top and bottom. However with everything wound down at the front (about 5-6mm) at full droop the spring is unseated.

[Seriouslylotus]

Did you change the front brackets or leave the nitron brackets on???

[alias23]

I believe the standard fitment or nitron ones... I haven't changed those bits from memory.

[550superfast]

I'm told Cup R top mounts are needed to run the Ohlins - I'm assuming I have these though as mine were fitted from new at Lotus Motorsport.

Also shorter top eyes are available (front 15mm and rear 10mm shorter)

[Arun_D]

I believe I'm running the same brackets as Imran is, I certainly didn't have different ones fitted.  My rears are getting the 10mm shorter stems as part of the remedial work following the issue documented on my thread. Hopefully they are still compatible.

[Seriouslylotus]

2 hours ago, alias23 said:

I believe the standard fitment or nitron ones... I haven't changed those bits from memory.

that's your issue.....Ohlins brackets are slightly different to Nitron ones

[alias23]

Im pretty sure Arun and I have the same setup. When speaking to Russ at Mick Gardner Racing he said Nitron brackets should be fine. Maybe one to triple check again but he did say at the time of my ordering that the nitron/existing brackets should be fine.

[alias23]

Just been out and done a bit of measuring as this is for sure an area of focus for me with the car right now. My current measurements based on the measuring points highlighted by @550superfast and @Hangar 111.

Front 136mm (at full wind down no further thread - Full droop spring is unseated)

Rear 150mm (still probably 20mm of thread left and no issues with springs at full droop)

I have no idea @Arun_D how you're running 122mm at the front! Could we have a slightly different setup?

My worry right now is that based on the current front setup the travel that seems available in the shock is pretty low. See the below, distance between the bottom and the bump stop is about 15mm. 

 

[550superfast]

I am pretty sure the mounting bracket is different on a V6 to a Cup

[Seriouslylotus]

100% Gary.......

[PhilT]

I have the 2 way nitrons and car is set up as CupR: 126 F and 136 R. No issues with springs etc. I can't go any lower - I'd ground the splitter getting off the drive and its a flat drive and flat road, its just the slope from normal kerb height!

[KJD]

I’ve recently joined you guys in the Öhlins club and front ride height has been vexing me too.

I wanted to run factory standard road height so, with the standard shocks (and with 75kg in each seat and full fuel, as specified) measured everything (chassis height and wheel rim to wheel arch as a check) before I swapped over, intending to adjust back to that level.

Now with the Öhlins, to get standard front height (133mm roughly) I need to have the spring 5mm loose on full droop. If I wind off all the way height comes down about another 8-10mm. The spring is then flapping in the breeze (like Imran above).

This is with 15% softer springs (800/1050) than Cup R spec so they should let the car drop a bit more too.

This is also with the specific Cup R Öhlins brackets that are definetly different to Nitron ones (Dave and I know this! 😉). They hold the top mount slightly higher so drop the car down slightly. The top of the spring and collar of the Ohlins also fouls on the Nitron bracket.

I’m a bit concerned about the loose spring come MOT time but Russ reckons  I’ll be fine. We’ll see next March!

There is an option to have shorter top eyes (as some racers do, apparently) but you’ll run into other issues with having to preload the spring back up (again, according to Russ)

btw, thanks to Dave and Russ for all the help and advice getting me this far!

[alias23]

Thanks @KJD this info is helpful. So what are your ride heights now front and back?

Im assuming you also have more travel in the shock even though lower height with the ohlin spec bracket - correct?

[KJD]

My heights are the same as standard, out of the box, factory stock road settings. As they were before I started fiddling  

How that is measured is a box of frogs!

The manual says it should be 125mm loaded. I get around 133mm, as best as I can measure on my not perfectly flat patio. The important thing is that it’s the same as before.

Travel wise, this is what I’ve got when on the ground but unloaded.

Hard to get in there to measure, but visually it looks like I’ve got more.

btw; did you notice I’ve got yellow springs. The correct colour.😁 (thanks Russ).

I also notice you’ve already got the shorter end eyes Imran, so that restricts your options. The correct brackets definitely made a difference for me.

The rears, with the helpers, are no problem. There’s enough thread to lower the height quite a bit, but the helpers keep what would be an otherwise loose spring in place.

Did I mention my springs are yellow. 👍

 

[550superfast]

Now running at 126mm front and 137mm rear - all happy - more details later.

 

[alias23]

@550superfast looking forward to the update!

[550superfast]

I have ended up with 126mm / 137mm and could go lower if we tried. I have the correct top mounts/brackets as fitted to Cup cars for the Ohlins TTX dampers.
What we learnt is that 60 litres of fuel and a driver make about a 5-7mm difference, and more importantly bringing the back down lowers the front a lot too. 
At the front I have 9mm of movement on the spring when the car is jacked up, but Russ says this is just fine.
I don’t think I need the short eyes and I am at target ride height, and also worried with short eyes that it may foul the bracket - although Russ assures me they wouldn't.

My mechanic Simon of CMS http://classicmodernsports.co.uk/ spent a lot of time and effort getting it just where it should be - thanks to all who have helped, I am now looking forward to Silverstone GP on Tuesday