320mm Front Brake Conversion

GT3North

GT3North

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Hi Guys,

I'm strongly considering upgrading my factory front brake to a 320mm kit. I found the following from Motoren Israel... is there a better option out there
to improve braking performance? For those that have already switched to a 320mm brake, how improved is the braking?

R80/100 GS Paralever brake kit

3435000_2779.jpg
 
I've had a couple of bikes I've fitted the HE 320 disc conversion that uses the original 2 plot caliper. Certainly an improvement, but still lacking in any real power. Possibly for the best bearing in mind the weedy OEM forks and pressed steel top yoke?

I've ridden airheads with the original disc and a Harrison Billet caliper and that provides similar stopping power to the HE, maybe a tad better. Maybe.

The setup pictured above certainly looks like it would be better than either of the ones i've mentioned. I reckon it will twist the forks easily.
 
Wouldn’t twin discs be better?
I had a HE 320mm disc on a 100 GS PD and whilst better, all it did was twist the forks - like Cookie said
If I was going down the airhead route again, I would prefer twin discs
 
JohnnyBoxer said:
Wouldn’t twin discs be better?
I had a HE 320mm disc on a 100 GS PD and whilst better, all it did was twist the forks - like Cookie said
If I was going down the airhead route again, I would prefer twin discs
Click to expand...
I am sure everyone would prefer twin disks but it's not a simple upgrade.
 
Last edited:
I honestly never thought of the larger single brake causing the forks to twist.
That's a deal breaker for me. I would not want to convert it to twin disks. I may just leave it with the original set up and ride within its limits.
 
Two options (three if you included the Harrison 6 pot):
1. The HE kit as you've pictured, available from various re-sellers (Germany & UK) and direct from the maker (Germany)
2. ABM kit, as sold by Bikermart in the UK: https://www.bikermart.co.uk/BMW-R80GS-R100GS-inc-Dakar-Single-Disc-ABM-Brake-Upgrades

Lifted from a previous post:-
I've had both the ABM kit (came on a bike I bought), the HE I bought direct from the maker (he-supermotard in germany).
The HE kit as sold by SIebnrock, SWT and others for 300 Euro ish is a flat 320mm disc with adptor ring and longer bolts - which means its a hefty bit of kit, weighing the same as the original BMW item. Bit of a faff buying direct but IIRC it was quite a bit cheaper - and the money goes to the maker, a small manufacturer (might even be a one man band)
The ABM kit is a 300mm disc with an alloy carrier so no adaptor ring/longer bolts needed and is probably the one I'd go for if buying again despite the slightly smaller disc diameter. Lighter/better looking piece of kit IMHO. And if you want to use it with a four pot caliper ABM offer their own version. Uses a different mounting bracket to the one for the original Brembo P8. Caliper is a pricey £300 option. but I'm pretty sure the dimensions are the same as the 40mm Brembo (P4?) caliper as used on many 1990's Italian sports bikes and still available new for reasonable money
I've just ordered a new ABM 'Brembo P4' bracket from Bikermart as I plan to fit a ABM disc/Brembo P4 to another airhead - so will be able to confirm the above in the next week or so
Never had an issue with forks twisting, maybe because I've fitted a decent fork brace?
www.motoren-israel.com

Gabelstabi R80GS & R100GS hoher Kotflügel

AV Gabelstabi aus Edelstahl für R80GS & R100GS mit hohem Kotflügel Der Avino Gabelstabilisator wird aus 4mm Edelstahl gelasert, CNC gekantet, trowalisiert und ele
www.motoren-israel.com www.motoren-israel.com
Maybe more of an issue with the g/s forks (which I think is what Cookie is referring to?)
 
Last edited:
MikeS said:
So would everyone like twin disks obviously but it's not as simple an upgrade. Do you know of an easy way to do what you are suggesting?
Click to expand...
I did a twin disc conversion on my 89 paralever GS, a few years ago. I basically mimicked the set up used on the twin disc 'Mystic' models. I used 4 pot 16 valve calipers of the K series models, these obviously need machining to get the correct centralization over the discs. From memory I got the calipers from Moto bins or Motoworks, can't remember who. The most tricky part of the conversion is achieving a second caliper mount. I bought a new right hand lower fork leg, machined the lower spindle hole & then flipped the leg around to give me the second caliper mount. I finished the complete set up using the master cylinder from a 'Mystic'. I vaguely seem to remember that EBC made me some custom floating discs, so that the venting holes on the disc were in the correct orientation. It was all a bit of a faff, but a huge improvement over the 'wooden' feeling of the standard 2 piston set up. Using second hand calipers softens the effect on your wallet!
 
GT3North said:
I honestly never thought of the larger single brake causing the forks to twist.
That's a deal breaker for me. I would not want to convert it to twin disks. I may just leave it with the original set up and ride within its limits.
Click to expand...
I did the 320mm upgrade using the standard calliper and it was better than standard braking and I did not notice any twisting. I plan to do it again if I get another Airhead GS.
 
GT3North said:
I honestly never thought of the larger single brake causing the forks to twist.
That's a deal breaker for me. I would not want to convert it to twin disks. I may just leave it with the original set up and ride within its limits.
Click to expand...
Not had that problem on mine which is the HE 320 disc with the standard caliper
Greatly improved over the decidedly wooden normal setup.
 
From what I’ve seen and read in various places the fork twisting issue applies to the R80G/S and can be reduced by fitting an aftermarket cast top yoke and a fork brace. The paralevers have sturdier forks and a half decent fork brace.

I bought the HE kit from Boxer Supplies intending to fit it before I went to the Pyrenees a couple of weeks back but had problems with the OE caliper (and found the modified 4 pot caliper that I’ve hadfor years wouldn’t fit the HE adapter plate without further modification). In the end my standard diameter EBC disc and 4 pot caliper with sintered pads worked find - quite hard work on some of the steep descents with lots of hairpins but managed to keep up!
 
Gelandestrasse said:
I've got a Boxer-toko https://bmwboxertoko.nl/ 320mm set-up and it is much better than standard. You won't look back.
Click to expand...
Another supplier of the HE disc set up. A lovely fella to deal with.
BTW, the Brembo P4 (and the Harrison 6 pot) will give you a better feel at the lever than the standard set up,.
I've got a machined 4 pot Brembo knocking about somewhere that was better than original twin pot P08 but not as good as the P4/Harrison
 
I've had the machined 4 pot on an R100PD and while it does make the feel a bit better, i'm not sure it's any more powerful (it also has to be mounted backwards).

The HE disc and original 2 pot Brembo P09(?) is a fair improvement for the money.
 
cookie said:
I've had the machined 4 pot on an R100PD and while it does make the feel a bit better, i'm not sure it's any more powerful (it also has to be mounted backwards).

The HE disc and original 2 pot Brembo P09(?) is a fair improvement for the money.
Click to expand...
With the TRW sintered pads apparently.
 
Aa lot of great options to consider for my girl.
This is how she looks at the moment. (obviously still working on rebuilding this bike so everything is new or refinished)

IMG_9232.jpeg

IMG_9231.jpeg
 
Nippy Normans supply Touratech, Wunderlich, Desert Fox and many other makes of accessories.
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