FSA 
Alpha Drive
MTB Cranks

  125mm to 153mm
Price $129 to $1??
Depending on chainring options

Prices shown good as of 6/23/2016
Prices include: Shortened Arms, Chainrings & All Bolts

Ordering, Payment, Shipping & Contact info.

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Outstate MN residents add 6.875% sales tax.
Metro residents add 7.775% sales tax
About the FSA Alpha Drive  8/9 Speed Triple
or 10 Sped Double Cranksets
Available with ISIS or Square Taper Spindle Interface

Outer 36t and 44t chainrings are 7075 Alluminum Alloy
Stock inner and middle chainrings are heat treated steel, but are ramped and pinned so shift smoothly and reliably. 

Triple rings are spaced for 8 or 9 speed indexed shifting and work with 8 or 9 speed chain.

Double rings are spaced for 10 speed indexed shifting and work with 10 or 11 speed chain.

10 or 11 speed Triple Alloy rings are available. But not cheap.

The triples all come with square taper arms and the doubles all come with ISIS arms. I usually have extra rings on hand, so all of the ring options shown can be fitted to either the ISIS or Square Taper version of the arms.

If you need a similar crank, but shorter than 125mm, I can shorten the SRAM S600 to 85mm.

BB spindle; ISIS or Square taper 113 mm will give a 48 mm
ISIS or Square taper 118 mm will give a 50.5 mm chainline.

For standard bike parts, it's always best to support your local shops. They should have a 320 gram Shimano UN-55 BB cartridge for about $30.
Or
I can provide 226g. ProMax SC-1  for $39.

For Fat Bikes I have 148mm FSA Platinum ISIS BBs to fit 100mm threaded shells for $52.

Q factor; 170mm with a 113mm BB spindle. Great ankle clearance.

Bolt Circle Diameter (BCD) The middle and outer ring are 104mm BCD, inner is 64mm.

"Safely" is a relative term. Modern cranks hopefully have a margin of safety to allow for the occasional 280 lb mountain biker. The Alpha Drives are pretty beefy wherever I put the new pedal hole.

Unless you are a smaller rider, or on a recumbent, Knee Saver type pedal extenders should  not be used with these cranks.

Temporary Price Reduction
I got a good discount on my last FSA order. So take $10 off all prices shown below.
8/9 Speed Mountain Triple $129
Square Taper Bottom Bracket

Alpha Drive with  22/32 Steel & 44t Alloy 8/9 sp. rings $129
Or, Alpha Drive with  22/32/44t Alloy 10 speed rings $209
(153mm shown)
10 speed Mountain Double w/Guard $139 - ISIS BB
 
The teeth of the 36 and 22t "Double" chainrings are cleverly offset outboard. So you get a proper "Double" chainline on triple crankarms.
22t inner ring is heat treated chrome moly steel
36t outer ring is 7075 Alloy

The stock guard it lightweight plastic. Good for keeping the chain from coming off or keeping your pants out of the chainring. But for a proper BASH guard see the options below

Scroll down for more Chainring Options 
Also available with 23-33-44 Rotor Q-rings
$399 on Square Taper or ISIS arms
Race Face Narrow-Wide Chainrings
These rings keep the chain from coming off, without retention systems. Review Here.
Alpha Drive with 30t Chainring (150mm Shown)
$165 for 32 or 34t or $179 for 30t
In order to fit a 30t ring on a 104mm Bolt Circle, the female part of the chainring bolt is machined as part of the chainring, adding to material and machining cost.
Available in Black, Blue, Red, Lime Green, Orange & Purple 

30t get black steel chainring bolts. For chrome add $6
Race Face rings are CNC machined from ultra hard 7075 aluminum.
These rings need 9, 10 or 11 speed chain for the chain retention to function properly. You can run 9 spd, chain on 8 spd. cassettes.
Two Chainrings & Rugged
Polycarbonate Bashguard


10mm Thick Polycarbonate Bashguards
are lighter & tougher than alloy guards.

  Gravity guard with 22-36 rings.  $185
A bit spendy because I have to use extra long female nuts from one set of chainring bolts and oversized head male bolts from another set
Also available; Truvativ Poly
Bashguard
with the 22/32 rings from the triple. $175

If you want the 30t Race Face ring, or to use the 22/32 rings from the triple as a double: To optimize the chainline I recommend 2mm Wheels Mfg. spacers be installed between the frame and the flange on the right side of the BB. I can provide these for $2.


22/36 no guard $139-->

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