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Posted by: Spoke Feb 8 2006, 04:43 PM

I'm doing a 5-lug conversion for my new 914 and need some help understanding the differences in front 911 calipers. I've seen "A", "M", and "S" calipers referred to. What's the difference? Which one(s) should I try to get? Lastly, anybody got a set of front struts/rotors/calipers?

Thanks,
Spoke

PS: If this topic has been covered before, please forward the link to me.

Posted by: TimT Feb 8 2006, 04:53 PM

A & S are the same sized caliper, S is aluminum, A is steel (iron), the aluminum calipers flex under heavy braking, also the A & S have 3.5" mounting bolt spacing. These have a larger pad than the M

M calipers have a smaller pad than the A & S, are iron bodied, and have 3.00" mounting bolt spacing.

Any of those calipers will work fine, S calipers command a premium

I have a comlplete 911 front end M calipers with vented discs ( this was from a 911 T with S package)

Posted by: Aaron Cox Feb 8 2006, 05:09 PM

couldnt have summed it up better meself...

i find that M calipers with an agressive pad are more than adequate to make my car stand on the nose.......

S calipers are $$$$$$$$$$$$$$$


An m caliper front end is anywhere from 200- 500
an A caliper front end is 500-800
Add a couple hundred to the above for S calipers....

Posted by: Eric_Shea Feb 8 2006, 07:55 PM

What she said...

You might want to equate it to cars and struts while your searching.

Boge struts came with the 911T. They're the most common out there in the early car range (69 through 73). The had the 3" mount spacing and hence the M-Calipers

Koni and later Bilstein struts 'generally' came on various 911S models and could be ordered as an option. The S models in those years had the S-Caliper. They're aluminum and a bit pricey but you can find rebuildable examples for $100-200 each. I've never felt the flex but... others have. Some 914-6/GT's came with them and given the power ratio on a 76 930 (which also had them) They are good for 914's up to 240-250hp. DaveP had a friend who tried them all and said that anything beyond an S-Caliper (A-Caliper as well as an example) is overkill.

Later (911 and 911SC) front ends had the A-Caliper. As described above, same pad size (but not depth) as the S-Caliper. I like the earlier front ends as they're set up for through-body bars. That being said the late model front ends can be retro-fitted with the U-Tabs and all should be fine. And, to add to that, if you're just looking at struts and not complete front ends... you don't have to worry.

If you're going the 'strut only' route you'll need to make sure your ball joints match.

E.

Posted by: Eric_Shea Feb 8 2006, 07:58 PM

You might want to be careful... if you stop too fast, you might get rear-ended!

Posted by: TimT Feb 8 2006, 08:10 PM

QUOTE

I've never felt the flex

its not that you really feel the caliper flex, you find out the calipers were flexing when you pull the pads and they have a wierd type of wear

Posted by: brp914 Feb 8 2006, 08:14 PM

huh? whuzzat? one willingly pays a premium to have his calipers flex!? Isn't the whole idea behind a monoblock caliper to have less flex? And it being aluminum having the benefit of better heat dissipation and less unsprung weight?

as far as stopping quickly, when cold a regular 914 caliper will stop just as fast as an "m" or even an "a". The question is fade resistance and modulation. Or are you saying there are tires out there so sticky that the caliper is overwhelmed? but even then, this can be compensated for with pad selection.

Posted by: TimT Feb 8 2006, 08:21 PM

QUOTE

Isn't the whole idea behind a monoblock caliper to have less flex? And it being aluminum having the benefit of better heat dissipation and less unsprung weight?

There is a world of difference between a 60's vintage aluminum S caliper, and a 00 vintage monoblock, there is no comparison.

The S calipers are desirable for their lightness, and period correct look to some

Posted by: Eric_Shea Feb 8 2006, 08:23 PM

He be right as well... which is why with a stock 914, and a 911 front end, the M-caliper is perfectly fine as Aaron eluded to.

The bigger the tire then you might want to look for big-ole calipers.

Buy Tim's 911T front end.

Posted by: brp914 Feb 8 2006, 08:53 PM

hey, dont you me. I invented !!!

Posted by: Headrage Feb 8 2006, 08:57 PM

I have "A" calipers...





They are sitting in storage right now.

Posted by: Eric_Shea Feb 8 2006, 11:16 PM

I do believe it twas I who invented the

You'll have to ask Sean

It was actually in http://www.914world.com/bbs2/index.php?act=ST&f=2&t=40896&hl=eric,and,shea,and,deadhorse.

Posted by: Cap'n Krusty Feb 8 2006, 11:35 PM

IIRC, M calipers use the same pads as the ones that came stock on your teener. The Cap'n

Posted by: Eric_Shea Feb 9 2006, 12:05 AM

And your point is?

Posted by: craig downs Feb 9 2006, 12:27 AM

So does this mean with the M caliper struts do you have to use the older style ball joints with the thru bolts

Posted by: Spoke Feb 9 2006, 07:45 AM

Thanks, I needed my morning chuckle.

If I don't get an entire 911 front end with torsion bars, A-arms, and sway bar, I'll use the t-bar, a-arms, and sway bar on my 71 914 which are from an 81 Carrera.

From the feedback, it seems that A calipers are good, followed by M calipers, with S being the best.

Spoke

Posted by: Eric_Shea Feb 9 2006, 08:16 AM

QUOTE

So does this mean with the M caliper struts do you have to use the older style ball joints with the thru bolts

No. I believe the 911 switched to the newer style ball joints 1-2 years before the 914. You just have to wcth for mis-matches and now the differences.