ST205 Calipers with different discs?? [Archive] - Woodsport Forum & The TB Archive

robd

08-07-2009, 17:26

Hi, I'm looking at getting some ST205 calipers for my mk1 & just wanted to know(excuse my ignorance) what would happen if I didn't use the ST205 discs, say if I just went for some scooby discs or something like that? I know the ST205 disc is 315x32mm & you need to machine it down to 300mm, but if I got some scooby discs which are 294x28mm(I think) would they work? I am guessing it would mean the pistons had to push the pads an extra 2mm on each side of the disc, would this affect braking/pedal travel or work at all?

Main reason I was thinking about getting different discs as I don't want to machine down the ST discs plus ones like from a scooby are cheaper & you can get grooved ones off ebay for about £70, so would be cheaper & easier in the long run. I know I would still need to drill 4x100 holes as the scooby is 5 stud.

Any help would be great.
Cheers
Rob :)

Jim-SR

08-07-2009, 17:57

spacing is your biggest issue. the discs arent just a diameter, they will sit further away or closer to the caliper, so then you may need spacers too. ST205 discs are easy to machine, and the discs last a fairly long time. using discs from a different manufacturer entirely poses more problems than its worth, otherwise someone would have done it already

robd

08-07-2009, 19:15

Ah right ok, what about if I was able to get discs from another car that were say 298x32, would that work? Think the supra twin turbo ones are 32mm & just under 300mm! Is there an issue with going below 300mm on the disc size, like will there not be enough disc for the caliper to push against? I suppose really whatt I want to know is what is the main thing to look for, is it the 300/298mm etc is it more the 28/32mm etc?

Any idea how much it may cost to get the discs machined down to size?

Thanks :)

biteme

08-07-2009, 19:17

That's the JSpec Supra disc.

UK Spec (aka Export Spec) discs are 325mm

Gary Symons

08-07-2009, 19:22

As jim said the biggest issue will be finding a disk with the correct offset.
Where in the country are you? Adamh on here may be able to machine the disks, he is down south.

Also [shameless plug :shifty:] I have a full st205 setup for sale, see the link in my sig below.

robd

08-07-2009, 19:33

Ahhh right I see what you mean, sorry I wasn't thinking straight! So the offset of the disc will affect the wheel offset! Doh...I was just thinking about it from the size point of view! Doh! Makes so much more sense now! (hangs head in shame) lol :)

In which case then yeah I guess I'll stick with the ST205 discs.

I'm near Cardiff in South Wales. :)

Thanks for your help everyone. :thumbsup:

Oh also, do the ST205 calipers just bolt straight on or do I need to mod them at all other than getting the discs machined?

robd

13-07-2009, 15:25

Just wondered if anyone can help, I've tried searching the forums but can't seem to find what I'm looking for! Could anyone tell me all the mods I need to make to the ST205 discs & calipers to fit them to the mk1?

I know I need to get the discs machined down to 300mm & drill the 4x100 PCD but do I need to do anything else?

Any help would be great as I'm hoping they will turn up this week & want to get them on the car asap.

Cheers
Rob :)

P.S. Also if I fit the ST205 fronts but don't change the rears are the rears likely to lock up a lot?

snowtigger

13-07-2009, 15:54

No the fronts will lock up first before the rears with st205s,have you got the spigot rings for the front and the drill and tap and bolts to do the hubs.

robd

13-07-2009, 16:29

No I haven't got any spigot rings, what size do I need? Is there a thread that I can use as a checklist? What do I need to do on the drill & tapping front? :)

Gary Symons

13-07-2009, 16:33

No I haven't got any spigot rings, what size do I need? Is there a thread that I can use as a checklist? What do I need to do on the drill & tapping front? :)

Pauls original guide is in Twobrutal filestore here:
http://forums.twobrutal.com/downloads.php?do=cat&id=1

robd

13-07-2009, 16:54

Brilliant stuff, thanks very much. :D

Has anyone ran the ST205 fronts with standard Mk1 rears & the Mk2 brake master cylinder? Just wondering if I can get away with running it like this until I get the rears upgraded to Mk2 calipers.

Jim-SR

14-07-2009, 09:14

you can just use M12 bolts with nuts on the calipers through the upright. make sure they are high tensile bolts though, personally id go 10.9 or better, but 8.8 is the absolute minimum.

robd

14-07-2009, 10:11

Cool, so I could do that instead of tapping the hub holes & drilling the caliper holes? Would it be safe to use the M12 bolts with nuts or would I just be better off doing the tapping/drilling? :)

robwsurf

14-07-2009, 10:14

dont think you ll have room for nuts to be honest

snowtigger

14-07-2009, 10:42

Never use nuts and bolts to fit calipers always use the method that the manufacturer used to fit the caliper to the hub, as you would have to drill the bolts and wire lock them so the nuts don't unscrew and dont fall of.

I've seen too many missing caliper bolts, I don't piss around with brakes as they are the most important part of a car.

robd

14-07-2009, 11:55

Think I'll stick with the tried & tested way then. :)
Hopefully they'll turn up this week & I can trial fit the calipers behing my wheels & see if they actually fit! Fingers crossed!! :pray:

snowtigger

14-07-2009, 13:07

Gary has done a paper template that you can put in your wheels to see if you have any issues with fitting your wheels, you may not be able to down load it if your not a big member though?.

Gary Symons

14-07-2009, 13:09

Gary has done a paper template that you can put in your wheels to see if you have any issues with fitting your wheels, you may not be able to down load it if your not a big member though?.

http://forums.twobrutal.com/showthread.php?t=15205

snowtigger

14-07-2009, 13:14

:swear: me that was quick do you have a search bot that every time Gary is mentioned you can nail the post.

robd

14-07-2009, 16:10

lol classic :)
Yeah already printed that off & did a rough test but with the wheels still on, brakes have apparently arrived at home so will trial fit them 2nite if I can & then I'll know(keeps fingers crossed). :pray:

Thanks very much :D

Jim-SR

14-07-2009, 23:20

dont think you ll have room for nuts to be honest

theres plenty of space

Never use nuts and bolts to fit calipers always use the method that the manufacturer used to fit the caliper to the hub, as you would have to drill the bolts and wire lock them so the nuts don't unscrew and dont fall of.

I've seen too many missing caliper bolts, I don't piss around with brakes as they are the most important part of a car.

sorry, but thats just not correct. a high quality bolt and nut is far stronger than a bolt threaded directly into aluminium or pig iron.

theres no way the thread will back off if its torqued correctly. you dont lockwire the bolts when they are threaded into the caliper, why would a nut and bolt differ in any way? some cars ive worked on in the past used pre-loctited bolts provided in the brake pad kit to hold the caliper on. loctite is not your friend, its more often a bad fix for an inherent design flaw. you seriously dont want it on a bolt that you ever need to get undone again!

ive actually seen Mr Woods mention previously that he had problems with the bolts backing out over time on his ST205's, i guess on the original set he converted (with an M14 thread into the upright). a hand cut thread into poorly cast iron or aluminium is never going to be ideal. a nut and bolt of the correct grade will always be consistent, and in this scenario would be stronger. the bolts are in single shear either way you play it, so there is no benefit to tapping a thread, and plenty of drawbacks.

P.S. wheels are probably more important, and they are held on with nuts :D torqued correctly and they just dont come undone, and they are under the exact same type of load as caliper bolts :)

Marksman

15-07-2009, 06:59

Good points all.

I'd like to consider that with the drilled and tapped method the two holes are in the same plate. Therefore one can't rotate relative to the other. I'd imagine this would mean a tendency to resist shaking lose that a pair of nuts would not have. To keep everyone happy how about drilling and tapping the holes and then putting a lock nut on the back :hidesbehi

Owen.

Paul Woods

15-07-2009, 07:53

ive actually seen Mr Woods mention previously that he had problems with the bolts backing out over time on his ST205's, i guess on the original set he converted (with an M14 thread into the upright)

Yep this happened once on my caliper set up, but i used a stupidly large pitched tap and i think that was half the problem, since then i have been using a much finer pitch and threadlock on the bolts, no problems with backing off since.

snowtigger

15-07-2009, 10:41

I'm happy to be wrong on more than one occasion and have seen caliper bolts missing from loads of cars when I was a mechanic,oddly always the bottom bolt very rarely the top and still work, have even seen the bolt method with high tensile bolts and nuts correctly torqued and thread locked and wired on my uncles race cars shear the bolt either method has its draw backs, what I am saying is if a manufacturer spent gazillions on a design that they didn't want sueing over if it ever whent wrong and god forbid failed, as has been said correctly done there shouldn't be a problem but for my 2 pence and peace of mind I will go with the tried and trusted method.

At the end of the day it's advice if he chooses one way over another then fair play or even an amalgamation of the two methods nothing in this life is 100%.

snowtigger

15-07-2009, 10:42

Gary Symons

15-07-2009, 10:56

I dont see how a nut can be used?

http://www.mr2mk1turbo.co.uk/photos/st205bolt.jpg

Jim-SR

15-07-2009, 12:47

i had mine with bolts on the outside, nuts on the inside (e.g. bolt head on the left in that picture, nut on the right). there was a lot more space than that, strange?!

robd

15-07-2009, 23:53

I have another question please :)
I measured up my calipers 2nite using the ST205 caliper template & test fitted the caliper..looks like the caliper clears the inside diameter of the wheels no probs...but it doesn't clear the spokes!! Looks like I will need 40mm spacers to get it to clear the spokes(if I've measured it right!!).

This may be a question for a different section but has anyone used large spacers on their Mk1's when using wide arches etc? Not sure what offset my wheels are but if they are say +5 or +40 offset....if I used 40mm spacers would that completely wreck the suspension setup & change the way the car handles for the worse?

Any help would be greatly appreciated on this as I'm a little out of my league here...if you hadn't guessed already!! lol :D

Thanks in advance :)

Jim-SR

16-07-2009, 12:21

not clearing the spokes is the biggest issue with clearances on the ST205 setup. even some 17's suffer! its because the manufacturers use cheap materials and have to beef up the material in these areas for strength. typically if you go for good motorsport manufacturers their wheels are better for clearance. the likes of Team Dynamics, OZ, Speedline, RAYS, etc.

40mm spacers wouldnt be ideal for handling. if you need THAT much clearance then id suggest considering new wheels. Team Dynamics Pro Race 1.2's can be had in 16" x 7" for £300 brand new for a set.

robd

16-07-2009, 13:24

Hi, thanks for the help. The spokes on my wheels are actually not too big, it's just they curve back in towards the back of the wheel so the wheel has a dish. Gutted they don't clear the back of the wheels as these wheels were free & don't really wanna dip into my budget for new wheels.

If I've measured it up wrong & I didn't need such big spacers what would you say would be ok to use..like 20mm? What do people who have the woodsport wide arches do...do they just get bigger wheels so they fill the arches or do they spacer the wheels out? I'd be more than happy to get the Woodsport arches as I think they look sweet, but don't really wanna ruin my handling & cause other problems if I have to use whopping spacers!!

Anymore help & info would be great. :)

Paul Woods

16-07-2009, 19:31

not clearing the spokes is the biggest issue with clearances on the ST205 setup

Tell me about it jim! I had to shave the word "celica" off the outside of mine to get 1mm spoke clearance, my spokes jammed on the letter C first time i fitted them lol

robwsurf

16-07-2009, 22:39

i have 15mm spacers each side on mine to clear spokes and wheels are still just inside arches might get away with 20mm and standard arches

hubcentric spacers try venom motorsport their good and cheap

adamh

17-07-2009, 00:16

hi rob, just a note to clear up any doubts Incase you went ahead with drilling and tapping.

The thread we use is an 'M14 x 1.5' and as jim says a 10.9 grade or better is used. If your not upto drilling and tapping take it to an experienced machinist , it will take him no time to throw up on the drill and push a 12.2 or a 12.5 hole through then tap it thru, he probably wouldnt even charge you.

An m14 x 1.5 was chosen for the origonal modification many moons ago, to complete the modification it was the next size up, naturally the next choice.

what advantages does it have over standard m14 x 2 or even standard caliper m12 x 1.5?.....
the m14 x 1.5 has a smaller helix angle than the m14 coarse or even a m12 x 1.5 (fine pitched o.e.m), due, to its increased major diameter. The smaller helix angle increases a bolts ability to resist self loosening, also the depth of a fine pitch form is reduced, so a greater cross sectional area is present, a greater cross sectional area of course gives a greater tensile strength. that is why the m14 x 1.5 was used, it wasnt guessed.
otherwise we may have still been using an m14 x 2!. its not rocket science dude but just to match the o.e.m spec helix angle or exceed it is sensible. a standard m12 thread by the way is worse than all the afore mentioned threads.

at a bare minimum you'll want a fine pitched high tensile bolt, if you can get away with m12 then no problem, st205 used m12 fine i believe, follow the torque spec for the st205 caliper set up, you've done as best as you can.

good luck man :)

robd

17-07-2009, 09:57

Thanks very much for all the info everyone, think I'll go with the drill & tap method & see how I get on. Just to check I'm getting this right, so I drill the hub holes & then tap them with a 14x1.5 tap & just drill the caliper holes out to 14mm so the bolt will slide through the caliper & then bolt into the 14x1.5 hub hole? Sorry if I'm repeating this just want to be 100% sure what I'm doing. :)

Also I have another question(promise I'll stop soon!!). If my current wheels were an offset of +5, I then fitted 35mm spacers would that then give me an offset of +40 or -30? If it gave me an offset of +40 would this be ok as isn't the Mk1 std offset 35 & it can take 40? I could be barking up completely the wrong tree here but just trying to get my head around it all! Is it mainly the offset that affects the cars handling or is it also the fact that the wheels are further away from the suspension so this would affect the handling?

Any more help would be great. :thumbsup:
Cheers
Rob :)

Jim-SR

17-07-2009, 12:29

+5 with a 35mm spacer would end up with -30. if youre already running +5's then you need new wheels, the handling will already be suffering.

std AW11 is +38 iirc, i wouldnt venture down past +30 personally unless you know what youre doing and youre changing geometry (and im not talking toes and cambers, im talking the fixed suspension geometry). when fitting wide arches people should be looking to increase rim width, not use spacers really. i dont see them as a styling modification, although many do.

adamh

17-07-2009, 19:27

Thanks very much for all the info everyone, think I'll go with the drill & tap method & see how I get on. Just to check I'm getting this right, so I drill the hub holes & then tap them with a 14x1.5 tap & just drill the caliper holes out to 14mm so the bolt will slide through the caliper & then bolt into the 14x1.5 hub hole? Sorry if I'm repeating this just want to be 100% sure what I'm doing. :)

HI rob, is correct. use from 12.2-12.5 drill for that tap in the hub. and a 14mm drill to clear the caliper hole out. i doubt you'll pick up a m14x1.5 bolt from a regular store, go to a fastener supplier direct.
go here and pick these up x 4 @ £1.50 each. you can trim the lengths as required. also dont quote me on the length i dont have a st205 set up infront of me, assuming 35mm of thread is plenty to play with. I got the tools/tap here if you want to use them pm.

http://www.taylorfasteners.co.uk/store/index.php?target=products&product_id=24287