EXTREME MAKEOVER........Steamer Edition

[geno955i]

:?:  hey mustang did you ever get a chance to take measurements of the brackets etc or consider doing a kit for sale?

[Mustang]

No
I havn't  had any reason to take the front wheel off of tigger 2 lately and to make a kit for such a limited market just doesn't make a lot of sense.

they are just 1/4 inch plate cut to shape to fit the calipers and to extend them backwards enough to fit the bigger rotors of the sprint or trophy .

[MtheTiger]

I havn't had any reason to take the front wheel off of tigger 2 lately and to make a kit for such a limited market just doesn't make a lot of sense.

I agree with that Mustang although a lifesize (1:1) tech drawing of the bracket would B verrry nice indeed especially for the exact placement of the holes :)  8)

[MtheTiger]

..........installation was a snap , just use the Tiger wheel spacers and it bolts right on and mates up to the Trophy brake rotor just like it was made for it

1 question though: does the Tigger sprocket fit the Sprint/Trophy mount?

[Mustang]

yep the sprocket carrier is the same part for the trophy rim as the tiger hub
sprockets will bolt on from either bike  

[MtheTiger]

Mustang, with which grade bolts do you bolt the caliper to the bracket?

- 8.8
- 10.9
- 12.9

I can get 12.9 which are the hardest bolts available but these are the least shear resistant and shear/break off without warning. Furthermore, the bolts I can get are fully threaded so the lateral force is put on the thread where it goes through the bracket.

I wasn't planning to launch myself in a hedge or worse under heavy braking :shock:  :roll:

As you can tell I have no clue whatsoever which lateral (shear) forces these bolts have to withstand..... :?:

thx

[Mustang]

I used 8.8's but the 12.9's will work just fine ....
you will have no problems

[MtheTiger]

Thanks, I'll go with the 12.9 ones.

[Bixxer Bob]

What diameter are the bolts? :?

[Mustang]

if memory serves me they are M10's

[MtheTiger]

Yep, M10 but Metric fine threaded (1,25) !
Hard to come by in NL & elsewhere I guess.

[Bixxer Bob]

Just for fun I did some numbers on this.  Apologies in advance for the simplification of the scenario:

Assume bike plus rider is around 750lbs and CofG is midway between front and rear wheels.
Assume that anything over 1G stopping force would cause a stoppie :shock:
Dist from front axle to disc bolt ring is around 10cm, dist to CofG is around 75cm therefore using simple lever / fulcrum calc the load at the bolt ring at 1G braking is 5625lbs.
Combined surface area of 6 bolts is around 0.5 square inches.  Yield point (lower than tensile strength) of the lowest grade stainless steel (I couldn't find a figure for 12s) is 185k lbs per square inch.  Shear is thought to be 4/5 tensile strength therefore max load is now 4/5 of 185k which is 148k lbs per square inch so the combined strength of six bolts is half of that which is  74,000 lbs per square inch.

Going back to the load of 5625lbs, safety factor for shock loads is x 12 so the notional load would be 12x5625 which is 67,500lbs.  So it can be seen that for the sake of this simple calculation, the max load of 64.5k is well within the max strength of 74k lbs.  Or to put it another way, 13 times as strong as needed.

This simple calculation does not take into account fork dive under braking, the friction strength created by the disc being bolted tightly to the wheel or fat blokes in the saddle.  And this is only for one disc and we have two ... or the role played by the back brake etc. etc.

And I need a lie down....    

[John Stenhouse]

You definitely need to get out more. :lol:

I would love to have that sort of knowledge though.

[Bixxer Bob]

...I would love to have that sort of knowledge though...

I've over simplified it because of the limitations of my education.  Most of that is either "O" Level physics (anyone remember "O" Levels?  must be worth a degree at least these days.. :roll: ) or knowing where to find the table to look up the numbers.  I have a doorstep of a book called Machinery's Handbook given to me by my boss when he retired.  Purchased today it would cost around £83. I was 22 at the time.  The book was printed in 1957, two years after I was born, but still relevant today.  It's gotten me out of a hole more than once!!

[MtheTiger]

Great write-up !

It's all waaaay beyond me but the conclusion is nice to hear!
Although it's not the disc bolts I was talkin' 'bout but the caliper bolts (2x2).

I guess the same force is applicable to these bolts 'cause the caliper and pads themselves create the -1G stopping force which in your calc is transposed to the discs..... the direction of the force is perhaps 180 degrees the other side...... :roll:  :roll:  :roll: :roll:

thx mate!