Tyre offset with scootrs disc brake fitted

[mugello74]

Hi Folks!

I am facing some serious tyre offset (10mm) after fitting some scootrs anti dive disc brake.
My mate and me checked everything twice but couldn´t notice what is going wrong.

Following parts were used:

jigged SIL fork from mike phoenix which was completely stripped. (used but checked)
"washer type" top ends for rod/spring (new)
SIL springs (used by me, like new)
MB SS rods (new)
SIL balls (used by me, like new)
clip in rubber buffers (used by me, like new)
MB drum links with damper studs (new)
tons of grease

Springs, balls and rubber buffers were used from a donor fork used in this scooter before.
These parts have very few miles and dont show any wear.

These parts all went together very well and didnt made any problems.
Tyre offset was measured from rim to inner fork leg on both sides and is about 10mm.

The actual version of the sticky spanner manual says that this happens on some early vesions of viet disc brakes and that some tyre offset will cause odd handling, uneven tyre wear and pulling towards one side under heavy breaking.

All of this points are non acceptable for me because the idea of fitting an anti dive disc brake is to IMPROVE scooter handling and braking behaviour.

How can i solve this problem?? pls help.

note: I would let loose that south east asia part and get a pm product. This is maybe a bit too radical to the effect that many guys are having this product fitted.

[soulsurfer]

I had this with a mate's last weekend, I replaced the spindle nut with a half nut which helped, and that made the dome nut bottom out before tightening correctly

[frank sanderson]

This is not only a problem with your anti dive hub its the same with most outboard disc hubs that use a lambretta style half hub ,basicly these type of hubs require a specific unit width to get all the nescercary components beetween the gap beetween the lambretta trailng links.It is possible but not always with the rim running centraly . The distance beetween the trailing link dropouts can vary quite a lot on lambrettas that is why our hubs are supplied with loose washers to space them centrally if the links are wide set. if the links are at the narrowest width I have found of 132 mm on std original lambretta forks our hubs will sit centraly, at this narrowest distance lambretta styled ouboard discs may not even fit nesecitataing the splaying out of the links which is not advisable as it can cause the internal components to rub within the fork tubes . Also worth noting is if your trailing links are wider than the hub you are fitting you should not just tighten the spindle bolt up and pull them inward this will have the same effect as splaying the links outward and cause friction and wear .if they are wider than the hub extra washers or spacers should be used to centralise the wheel and assure a relaxed fit.Most trailing links are quite similar in relation to the offset of the trailing link spindle mount to the pivot bush housing so just changing links for another set will prob not solve your problem. If you want to persevere with your scootrs anti dive hub and set it centrally you could always swop your links around so that the dropouts point outward this will give you loads of room but you would need to reposition any damper brkts and make spacers to fill the gap beetween the hub and the links. We have loads of customers with the same issues and have found that this is sometimes the only way to get the hub to mount centrally.You can see an example in the clinic sect of my website www.lambrettainnovation@yahoo.co.uk

[carlos fandango]

Ive had the same problem with a sterling disc brake, tried different things to get it central but to no avail
In the end i took it apart and got the hub machined down to move the disc, caliper and speedo drive housing nearer to the center, then used washers the otherside to pack it over. Machineing cost about £20 add on to that labour charges if you had to pay someone to do it all and i would guess at £100 in total to have a hub central as it should be. So £200 for the disc kit and £100 to have it set up properly £300 for a "cheap' asian import
My other scoot has a frank sanderson antidive on it and this works out cheaper than the other ones and better quality So buy British :bouncyeng:
Having said that i prefer the look of the std. hub Perhaps this is something Mr Sanderson could work on

[soulsurfer]

Having said that i prefer the look of the std. hub Perhaps this is something Mr Sanderson could work on

Already done...

[red ghost]

Or you could make your own;

[scootRS.com]

>>This is not only a problem with your anti dive hub its the same with most outboard disc hubs that use a lambretta style half hub ,basicly these type of hubs require a...

This isn't a problem we've seen with our disc kits, and we've fit them to quite a few models over the years. We've checked them, and we do scooters with disc kits all the time, and they are centred. Even our new version coming out with bearings worked into the caliper plate/tie bar is centred fine.

As per the original post, it was only one particular early version years ago where the hub was actually offset a bit but which we resolved for people back then when it was noted. However, Sterling apparently copied that and that's why those have an issue even now. Sticky isn't exactly the most informed person about Asian products

Presumably the only way it would not be centred would be if:

1) your links or something are offset on one side of your set up, no? (Frank notes link sets are a little different and some might be a problem but then says changing to another set would not fix it, so not sure what that means. Logically, even if some sets are a bit narrower/wider it would not offset a centred hub and a few mm tighter/looser won't make any difference to your links. Offset would only happen if one side was offset, right?) Have you checked that? Have you checked with other hubs?

Or 2) the hub is not centred for some reason, which seems unlikely, but in which case you would get a free replacement. You should check by measuring to the centre point from both sides of the disc unit only. Have you found that to be the actual case and contacted ScootRS?

You can also use washers to adjust a bit for some offset, or on both sides for wide links. The PM one would also be offset too if not adjusted.

Here's ours at the shop:

[carlos fandango]

Well that doesnt look central from that photo, there is a gap between the tyre and left hand link bolt and not the right side.

As frank said most link gaps alter thats why the Franks have washers to centralise them. He has identified a problem, thought about, it and soved the problem i think other manufacturers should take a leaf out of his book

Cue another ten pages

[scootRS.com]

Well that doesnt look central from that photo, there is a gap between the tyre and left hand link bolt and not the right side.

Sure, it is centred. The photo is from ages ago and was taken specifically to show that they are centred.

Also, you can adjust ours with some washers too, as noted, but that is not to centre a hub, it is to do with tighter/wider links as Frank explained. Frank's I assume is narrower so you can add more washers, but then again those disc kits require you to reverse your links, no?, which makes more room but is an awful task for the average scooterist.

If one link is bent, you should really fix that, not cover it up with washers on one side.

We haven't had any emails about offset disc kits, so no reason to change it. Just searched our email system for the past 2 years and nothing. Not sure we could even narrow it to allow for more washers on each side even if we wanted to.

Is this where Sticky calls for an investigation into Asian parts and posts random theories? -just to clear the air, of course, not scare anyone!

Cheers.

[10 inch Terror]

Without wanting to take sides on this one, i purchased an anti dive kit from a German dealer at twice the price of the Scootrs version, this too needed 'playing' with to get it to sit central in the links. So perhaps it's not just an Asian thing.