M140i Upgrades // Part 9: H&R Anti Roll (Sway) Bars

In the final part of the project series we take a look at the H&R anti-roll bars, fitted by DRW Performance (DW).
As mentioned in the video, please consider that I have only fitted the H&R ARBs to my car, any ideas about how the others may feel are just educated guesswork! :-)
Here are the different available bars' dimensions:
OEM F: 22mm R: 15mm
H&R F: 28mm R: 20mm
Eibach/KW/ST F: 28mm R: 16mm
Hardrace F: 28mm R: 19mm
Ultra Racing F: 27mm R: 16mm

[@jeremytownson1101]

Well done for putting up these vids after selling the car.

[@CIRCUITDRIVERCARS]

Thanks Jeremy, I felt like I learned lots by doing with the M140i project and happy to help with my experiences. Just a shame I had to sell it when I got to the point of it driving really nicely indeed...

[@alexanderdt5992]

A little bit of extra feedback for the M140I community (I already gave some feedback on an other video in this series, but I should have posted it under this video): For background: On the suspension/chassis side I have: - B12 kit - Mperf. diff. - Rear PF black bushing inserts - M4 LCA + TS - a sporty road alignment I installed the hardrace rear ARB, which to me in combination with the other parts made the car a tad too direct, in the sense that you have to steer it very precisely and gently in order to not upset the car. Especially in faster corners you feel like the car will rotate quite easily. When it goes it's quite controllable, but still not the nicest of feelings. On Spa-francorchamps track, in warm and grippy conditions, the car was enjoyable and fun, but definitely not a very "easy" drive. Fast corners you can definitely get some scary rotation if you're not precise and progressive with steering and trottle inputs. Again, fun, but maybe not for everyone. I will install the front hardrace ARB aswel and then maybe try to correct any understeer with some stickier rubber (I am running eagle F1's at the moment). Hopefully I can do a test this year still and report back.

[@eoghanhennessy15]

Has anyone tried the suggestion of fitting an aftermarket rear with the standard front arb?

[@NickthaGeek]

Are you sure the oem front is 22mm? Because powerflex do not list a 22mm bush at all. Smallest they list is 24mm...... Odd that powerfex do not offer a oem size bush...

[@MrAshLloyd]

Love your series bud and I’m now subscribed. Look forward to your final conclusions

[@Svrcko944]

I am also keen on trials with that. Especially to do rear only, as I preffer oversteer over understeer. On thing to take into the consideration with sway bars it’s that you rely on torsional stiffness of a cylinder (shape of a sway bar). So talking 15mm to 19mm is not 22% stiffer but rather 60% if 19mm sway bars are not hollow, if they are hollow torsional stiffness is up by 28%. Why is that? Because torsional stiffness is dependable od diameter to the power of 4 and not linear. Bear that in mind because small increase in numbers or type could mean much bigger difference. Thank you for this beautiful series, it’s really hard to find any objective or subjective information on most of the mods. It seems that most of the people are doing it for sake of having it.

[@CIRCUITDRIVERCARS]

Thanks for sharing, and very easy to overlook regards the increase in stiffness... 2mm might sound little but have a large impact, especially on other cars with very spindly rear bars. I have heard annecdotal reports from others since this video that the rear bar alone made a positive difference to the drive as hoped.

[@eoghanhennessy15]

@@CIRCUITDRIVERCARS Which rear did they go for in the end? The 19 or the 16... facing the same question now as I'm doing rear end work and could have arb fitted for low/no extra labour

[@GhazUK]

Great video and well explained! Do you think going for the 20mm rear ARB on its own is feasible? Do you think it will be fairly neutral? Edit: Now I've finished watching the video, you explained the rout I mentioned 😂

[@CIRCUITDRIVERCARS]

Since the vid I've heard from people that have done the rear only, some thought it was good, some thought it too oversteery, speaking to Birds they would only advise on cars with an LSD. Personally I think I'd now only advise with an LSD and if you have adjustable (damping) suspension, so that if it is a touch sharp, you can tune it out. ...or if you're prepared to fit a front bar too if you don't like the balance...

[@shaheedbenelbaida6454]

Amazing videos, helping me with my build 👍🏽

[@CIRCUITDRIVERCARS]

Thanks mate, enjoyed building the car and assessing it at each phase. 👍

[@Armada8589]

Really enjoyed watching your videos. Very helpful with my future 140i project. I love the track time inserts 😁 well done 👌 do you still have the car?

[@gerardjoaquino8856]

I finally put on some poly bushings on my MX5. Massive difference from before! Now i'm contemplating on a front bar. 🤔

[@CIRCUITDRIVERCARS]

It can't be really transformational can't it. Even more so if the existing bushes are worn. Is that on a mk 1/2/3 MX5?

[@gerardjoaquino8856]

@@CIRCUITDRIVERCARS mk1 1.8. Well, i decided to forgo the bars since my coilovers perform really well (D2 brand) and i want to retain the independence of movement between both sides of the axles... so i bought a 4age itb throttle instead 😅

[@CIRCUITDRIVERCARS]

@@gerardjoaquino8856 Couldn’t have chosen better myself!! On a mk1/2, I like the standard ARBs and as you said, the suspension independence. Sounds like you’ve built a cracking car! 😬

[@gerardjoaquino8856]

@@CIRCUITDRIVERCARS haha thanks! It's been winning some grassroots races lately. Only managed to get it running after 2 years due to a bad ecu. An ITB conversion is in the works now.

[@CIRCUITDRIVERCARS]

@@gerardjoaquino8856 oh you hero! Glad to hear it’s working now and all the best with the ITB conversion! Enjoy! 😬

[@NickthaGeek]

Been thinking about this and as soon as you mentioned the m setups being 3mm different between fron and rear.... then mentioned the hardrace 19mm rear instantly what I thought was having just the rear and fitting powerflex black bushes to front arb would probably be the best of the bunch inline with m cars. Thats the route for me by the sounds of it.

[@CIRCUITDRIVERCARS]

Certainly worth a try, especially since the rears are so easy to fit compared to the fronts. A couple of people have given feedback saying the car is well improved with just the rear bar. 👍

[@gregtodd1788]

@@CIRCUITDRIVERCARS - These are a great series of videos thank you! I have my car booked in this week for subframe inserts and am considering installing just the 19mm Hardrace rear ARB at the same time, but I'm a bit worried this will upset the balance and possibly will affect the ride too. Can you (or anyone with experience here) share any further thoughts and feedback from what you have learned so far from taking this route with the car? The garage I am using recommended to focus on the front ARB for a rear drive car, so I am a bit conflicted. Many thanks for any advice you can give! 👍

[@NickthaGeek]

​@@gregtodd1788As he said, theres 3mm difference front and rear on the m car... so by fitting a 19 on the rear, I would say it will make it more in line with that. For me, its the rear that is the issue.... Front feels ok.

[@k.alothman]

Turrner Motorsports makes F: 32mm R: 23 mm Wouldn't that be better than H&R ? 9mm apart and thickest in the business. Just afraid it would keep scraping the front endlinks.

[@acsmotorsportuk]

Something I’m keen to know as well. I’ve not found a UK supplier as of yet though. The rear is also adjustable too

[@scottfriesner1538]

Very informative!!!! Thanks

[@CIRCUITDRIVERCARS]

Cheers Scott 👍

[@martinlee7706]

good choice H&R , compare the OEM so light like a toys.....the H&R so heavy like a dumb bell..... my car atm on stage2+ thinking is it necessary to go stage3 ( turbo and chargecooler)

[@CIRCUITDRIVERCARS]

I've not driven a stage 3 car so have no experience, I think that's perhaps the point at which I'd step up to an M3/4/5 rather than taking a 1/240i any further.

[@Edstar-fh4rx]

Extremely informative video as always. A shame you've sold your m140i :'( But regardless, thanks for the video! Any more coming up in regards to the m140?

[@CIRCUITDRIVERCARS]

Thanks Edwin, I plan on doing one or two summary vids about my time with the car and thoughts about them and M cars in general. 👍

[@Edstar-fh4rx]

@@CIRCUITDRIVERCARS looking forward to them :P

[@jameslovett8697]

@@CIRCUITDRIVERCARS Would u recommend to others? Why did u sell it?

[@joelawson6596]

Great informative video, just wondering if you thought there was any merit to getting a set of adjustable drop links for the rear of the car too? Or was it just the front that really needs the adjustability? Thanks in advance.

[@CIRCUITDRIVERCARS]

Cheers Joe, I didn’t see any material upside so didn’t bother. Other Nat have a different viewpoint, but not something I would replace unless worn.

[@philipp594]

Do you think these are usable for street driving? I heard that the m links are a disadvantage when your suspension has adjustable camber, is that true?

[@figleafyogi]

Thank you for this informative video! Any suggestions for a 2017 M240i xdrive? I just purchased one after selling my Audi S4 which had a rear sway bar installed.

[@pawellendzioszek5140]

Hi guys . I’m planning to fit lowering springs and anti roll bars on my m140i . Just wondering if I need to get drop links replaced aswell?

[@chidogg93]

Will you end up making the conclusion video?

[@CIRCUITDRIVERCARS]

Yes, promise... getting sorted out with the house now, along with lighter evenings time for filming vids should be easier! 👍

[@anthonyh958]

@@CIRCUITDRIVERCARS pull your finger out man! Lol I look forward to it. Didn’t even realize you released the last couple of videos as you sold the car. Good on you for doing this 🍻

[@vollcare4076]

Are all bars solid metal and not some hollow and some not? And all are basically made from same steel alloy, so that a thicker ARB will always be stiffer ?

[@CIRCUITDRIVERCARS]

Excellent points as ever mate, I’ll add the caveats to the description info! From what I could find all of the mentioned are solid.

[@simonlo7595]

@@CIRCUITDRIVERCARS may have missed your video earlier, why'd you sell the M140i?

[@MrAshLloyd]

Have you got a link for the adjustable drop links for the front?

[@CIRCUITDRIVERCARS]

I used posh Super Pro ones. but they fouled because they were quite thick. Whiteline do some that are thin and adjustable (just like threaded bar), or you could measure the right length and buy some fixed aftermarket or oem drop links.

[@TimChump]

Do you think its worth doing these modification on an M Lite or are you better off going for an M Car from a cost perspective if your final goal is a dynamically sorted car? I think the parts alone would be ok but when you add in the labour costs you could be looking at M Car Money to get where you want to be?....

[@NickthaGeek]

Problem being the m cars dont have a b58 up front.

[@MT-xy7fw]

tyres used?

[@CIRCUITDRIVERCARS]

Yokohama AD08R, Accelera 651 Sport and ContiSport 6 in the summer and at the track, Michelin Cross Climate+ in the winter. 👍