View Full Version : Hardened bolt for bottom shock mount?

05-05-2003, 03:53 PM
I'm trying to put on my new Penske, and I need a longer bolt.
The stock shock had 1 side of the mount threaded, so the bolt screwed right in there. The Penske, does not, and this bolt is not long enough to put a nut on there.

Anyone got any ideas where to get a slightly (1/2") longer bolt?

How did you mount your shock on there?

micah apriliaforum com
05-05-2003, 05:10 PM
Call your local fastener house.....they should have it in stainless or a high grade steel.....no worries. If you cant do that call me with the dimensions and I will see what we have. I can get it in Ti.....ahh the bling!

05-06-2003, 11:56 AM
that's a huge bolt, 10mm, i recall. you don't need anything special in there. :) chris

05-06-2003, 01:40 PM
Yea, I need a 3/8" x 2.25" bolt length under the head. Thing is that it's tensile strength/grade is 8.8. I asked a guy at Home depot, and he suggested I not replace it with something they have, b/c they don't have ones that strong, and I'd rather not have to worry everytime I'm on the track if that thing's gonna hold, know what I mean?

micah apriliaforum com
05-06-2003, 02:35 PM
If it is a 10mm bolt do you know the thread pitch?

05-06-2003, 04:25 PM
Went down to good ol' Northern Tool & Supply, and they had both US & Metric grades... They had a 8.8 but it wasn't quite long enough, so I grabbed a US grade 8 (highest it goes, I think) both in 2" & 2.5" (no 2.25"). So it looks like that'll do.

Micah, I don't know the thread pitch, it seemed to be 'standard', and really it doesn't matter as long as there's a matching locknut to go/fit with it.

05-06-2003, 10:18 PM
pitch doesn't matter on the penske, as it has no threads. you have to use a bolt and nut on it.

OEM shock: M10x45 (1.50 pitch, standard "coarse" pitch) with hex head

Penske shock: M10x50 (1.50 pitch, 1.50 pitch) i used stainless A2 socket head. note that the penske has steel eyelets embedded in the aluminum mount.

the OEM shock is threaded aluminum, wtf you need a 8.8 bolt for? the ally is going to give long before any steel bolt will. now, talking about thread pitch: brake calipers, those are M10x35, 1.25 fine pitch, which are somewhat uncommon. apparently only a couple of bolt vendors inventory M10x1.25 socket head stainless bolts.

3/8" bolts are .5mm or at least .020" smaller than the hole. you may get some movement in there... depends on the friction across the mounting surface area of the tabs. i suggest to most folks buying bolts for motorcycles to avoid the grade 12 black oxide bolts. they're too strong and do not like to be stretched. therefore, when subject to the vibrations of a motorcycle, they tend to show how brittle they are and will snap.

:) chris

05-07-2003, 06:41 AM
Thanks Chris...that was some great bolt tech!

05-07-2003, 06:49 AM
Right.. I just wanted to make sure I replaced what was there with the same or close to same thing. That's why I got a USC grade 8. I tried it last night, looks like the 50mm 'just' fits with the nut on there.

The good thing about the brake caliper bolts is that there are several models of the Aprilia that use them. When I needed one quick, I went to the local dealer and he had a few in stock :)

05-07-2003, 06:57 AM
So BTW Chris... are you saying a USC grade 5 bolt (say from Home Depot) would work fine for the shock bottom mount?

05-07-2003, 10:27 AM
Mike, where did you nuy the shock and how much was it?

05-07-2003, 12:07 PM
I got it from Traxxion - $749 shipped

05-08-2003, 01:11 AM
hey ecumike, i wouldn't hesitate to use any steel bolt there. i'd prefer M10... but i guess 3/8" is passable.

btw, i'm a penske dealer, too. :rollin:
i've got the specs for the only piggyback 900ss shock.

:lol: chris

05-08-2003, 04:21 PM
If you need the right bolt, I have 20 of them. M10x1.5 thread and 60mm long. Grade 8.8 and only 25mm of thread, so the shank is smooth. I used one to mount my Ohlins. Had to buy 25 for a minimum order. Give me an address and I will ship you one free.


05-08-2003, 05:07 PM
ehhh. sure. if you got a spare to send, tha'd be cool.
Shoot me an email, and I'll send you back my address... mike@santelia.org

Thanks a ton.