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Home made "Slammers"

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SaMAlex:
Slammer

I have been having a bit of trouble with my wheel slipping forward (usually from heavy Icepicks) so for a while now I’ve been wanting do to something to sort it out. I got some new wheels recently so it seemed like a good time.

Have done stuff in the past with rear facing chain adjusters but although they worked great, they didn’t look that good and I didn’t really want  to be welding stuff onto my frame. I also wanted something that worked with and without pegs, cos I like to take mine on and off.


(This is a mod I did to a challenger frame a good few years ago)







I like *SIMPLEBMX Slammer idea (even though there is no “adjustment”, and nothing you can do when the chain stretches) so I thought Id have a go at making some.

*(http://www.simplebmx.com/products.html#slammer/slammers)



First up, I measured what I need and sketched it up. I wanted a washer the same diameter as my pegs, with a “lump” to fill the gap in front of the axle. I made the lump longer than I needed so I could file it to fit later. I continued the Lump behind the axle as well. This was to help hold the slammer in line but also to stop the dropout closing up if it got hit when grinding. Finally, my pegs have anti spin pins so I wanted the washer to accommodate these.







Then I made a solid model of the sketch. I used ProEngineer which is pretty horrid but its what we use at my work.







From this I did a 2D drawing of the part and gave it to the workshop at my work to make.







2 machined parts







Then the hard bit, getting them to fit! I had to take quite a few mm’s off the front of the lump, and also make it nice and round to fit the curve at the front of the dropout. It took the best part of an evening to get them both done, but wasn’t too bad. I made them a tight fit, which I know isn’t doing my chain any favours, but I could always file more off if the chain was too tight, and I also needed to allow for the chain to stretch









I bit of cleaning up and they were ready to be sent to anodising (another perk of my job)







That’s better. Nothing but Black on my bike, thank you!







And there they are. Finished and fitted. They are quite a tight fit in the dropouts so when I take the wheel nuts (bolts) off they stay in place. This means that I can take my pegs on and off easily without the wheel moving. If I ever need to get the wheel out, I just pop the washers out and the wheel can move forward enough to drop the chain off.












I’m pretty happy with out they came out. Now I’ve got a whole weekend of riding ahead of me to see if they actually work!!

J Rolla:
Nice work  :coolsmiley:

JT71:
good work Mr Leech, they look great in the flesh too...and weightless, are they made out of helium infused ali?



so, think we had this convo already, your chain is your old one, so it is pre-stretched right?

SaMAlex:

--- Quote from: JT71 on September 17, 2009, 12:25 PM ---so, think we had this convo already, your chain is your old one, so it is pre-stretched right?


--- End quote ---


No, the chain is brand new  :-\

But hey, how much is my chain really gunna stretch? Its only short and its not like I do many "miles" on it. The cranks rotate backwards more than they do forwards!

firebird:
 :4_17_5:

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