Fastest mountain bike I have built!

bobo60

New Member
Nov 23, 2019
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This is a reply to those who fear using lightweight aluminum frames due to cracking issues.
I bought a used Diamondback Outlook mountain bike. All aluminum frame and as light as my road bikes.
I put a Zeda Firestorm YD100 kit fromBicycle-engines.com on it and it will hit 54mph on a
flat road for almost 2 miles. The YD is a torque monster, so even with a 36t rear sprocket, You can take off from a
standing start with little or no clutch slippage. It goes up hills and grades without missing a beat, and is
fun on the trails as well as the road. Here also is a video of it going on the street, and a spin on a local bike trail,
and then on the expressway.
20200630_205049 (1).jpg
 

MoonLitCreeper

New Member
Aug 7, 2020
10
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Nice bike,
Debating on motorizing my cannondale killer v500.. Its pinky weight and made with aerospace aluminum.. Would probably be better than my fuji mx600 series.. But the frame on the cannondale is really thick so id need bigger motor mounts, which i dont have atm. But its a sound idea lol
 

Sidewinder Jerry

Well-Known Member
Dec 19, 2011
1,418
277
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Rockwood, TN
This is a reply to those who fear using lightweight aluminum frames due to cracking issues.
I bought a used Diamondback Outlook mountain bike. All aluminum frame and as light as my road bikes.
I put a Zeda Firestorm YD100 kit fromBicycle-engines.com on it and it will hit 54mph on a
flat road for almost 2 miles. The YD is a torque monster, so even with a 36t rear sprocket, You can take off from a
standing start with little or no clutch slippage. It goes up hills and grades without missing a beat, and is
fun on the trails as well as the road. Here also is a video of it going on the street, and a spin on a local bike trail,
and then on the expressway. View attachment 106321
Can't tell from the pictures where's your speedometer or bicycle computer? Only looks like a cellphone is on it.
 

Nightster

Well-Known Member
Mar 3, 2021
726
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Texas
Can be as much as +/- 10 mph.
I’ve used several apps in a truck before and found them to be within 1 to 2 mph. wish I could remember the main one I used to use. Got a new phone recently and will have to go find it. Not saying they are great, just my experience wasn’t bad.
 

Nightster

Well-Known Member
Mar 3, 2021
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Here’s the one I used to use:

Speed HUD

For IOS:

 

Sidewinder Jerry

Well-Known Member
Dec 19, 2011
1,418
277
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Rockwood, TN
Here’s the one I used to use:

Speed HUD

For IOS:

Bicycle computers are cheap and much more accurate. Most generally require a millimetre circumference entry. Simply put a level on your front tire and measure to the ground for the true diameter. Mine is actually 26 1/4". Multiply by ⚻. If you took the measurement in inches divide the circumference in inches by 25.4. Then enter that number into your bicycle computer.

Example:

26.25 × ⚻ ÷ 25.4 = 2095
 
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Nightster

Well-Known Member
Mar 3, 2021
726
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Texas
BTW, I tried the speed HUD app on the way home last night. It was off by 2 mph, in the current truck I was driving. I find vehicle speedometer‘s not to be accurate amongst each either also.
 

Sidewinder Jerry

Well-Known Member
Dec 19, 2011
1,418
277
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Rockwood, TN
BTW, I tried the speed HUD app on the way home last night. It was off by 2 mph, in the current truck I was driving. I find vehicle speedometer‘s not to be accurate amongst each either also.
The only true way to test that is with a radar divice. I'm not talking about the ones on the side of the roads either. Those are purposely set to show a higher speed with the belief it'll slow traffic down some. Generally a motor vehicle's speedometer is set up for a particular tire and air pressure. Change that and it affects your speedometer accuracy.
 
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wheelbender6

Well-Known Member
Sep 4, 2008
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TX
Nice bike,
Debating on motorizing my cannondale killer v500.. Its pinky weight and made with aerospace aluminum.. Would probably be better than my fuji mx600 series.. But the frame on the cannondale is really thick so id need bigger motor mounts, which i dont have atm. But its a sound idea lol
The Cdale Killer V is a classic, so I wouldn’t motorize it. Find a nice steel mountain bike to motorize fort trail riding, I MHO.
 
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MoonLitCreeper

New Member
Aug 7, 2020
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The Cdale Killer V is a classic, so I wouldn’t motorize it. Find a nice steel mountain bike to motorize fort trail riding, I MHO.
Eh it was a thought for power vs weight ratio.. As of now the bike im running is a Fuji Mx 460, which is chro-mo but still light. With the killer V the down tubes are really thick so id have to make a special mount for the motor, which i dont really want to do. Tbh it was just a passing thought, when i saw this post i was like "what if" lol
 

Citi-sporter

Active Member
Jun 16, 2014
206
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North Bend, Or,
My bad there, you multiply by 25.4, sorry need more coffee lol

Example:

26.25 × ⚻ × 25.4 = 2095.
If you have a metric tape measure it's even easier, just place the front wheel with the valve stem down on a flat surface with at least 10' roll out forward clearance, mark the point on the ground where the stem is. Then roll the bike forward until the stem is at the bottom again and mark again. Measure the distance in millimeters or meters in length between the marks with your metric tape measure. And enter it into your bike computer. It's how we did in bike shops ever since the Avenir and Cateye cycle computers came out in the 1980's.
 
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Sidewinder Jerry

Well-Known Member
Dec 19, 2011
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If you have a metric tape measure it's even easier, just place the front wheel with the valve stem down on a flat surface with at least 10' roll out forward clearance, mark the point on the ground where the stem is. Then roll the bike forward until the stem is at the bottom again and mark again. Measure the distance in millimeters or meters in length between the marks with your metric tape measure. And enter it into your bike computer. It's how we did in bike shops ever since the Avenir and Cateye cycle computers came out in the 1980's.
Very inaccurate method. Just being a few millimeters off can alter your results.
 

Citi-sporter

Active Member
Jun 16, 2014
206
42
28
North Bend, Or,
Very inaccurate method. Just being a few millimeters off can alter your results.
As to can different tire pressure also result in a different diameter. Not to mention the squish factor of weight and knobby tires. your method if you get it off by a few mm gets multiplied by Pi. Having checked my bike's trips to the listed distance, I'll take a system that has worked for bike shops for decades. Thanks anyways