For starters, I have a "forward pedal" 7 speed beach cruiser...

Joined
Jul 14, 2017
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#1
It has 26 inch rims with cantilever brakes. I purchased this bike with hopes that I can eventually put an engine on it. I'm a noob as my name states, so please help any way you guys can.
I want to start off small and safety is essential. I was thinking of trying to modify it to disc brakes so it would have more stopping power. I think it may cost a lot to do so because I would either have to change the hubs or buy new rims.
The new rims would have to be able to allow my freewheel gears in back. The new hubs would have to be the same diameter as the current ones, so I don't have to change the spokes. And I don't think I want quick release because it seems unsafe to me.
The cruiser frame is not made for disc brakes so I'm told that I have to either weld tabs for the calipers to attach to, or buy some kind of special attachment piece.
I heard that I could try and swap out the forks for mountain bike type with shocks, so it has the attachments for caliper, but I'm not sure if the forks would fit the beach cruiser? (The shocks themselves might be good for the motorized bike though). Then that still leaves the rear, OMG!
Help! I know its a lot to read, but I'm new.
Thanks in advance,
-NOOB
 


Frankenstein

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Jun 24, 2016
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#2
Ok so I have seen videos where if you have a forward crank bike, there are rubber mounts you can put over the studs on the mounts of the engine. Check out; "JNM Vibration Motor Mounts"

And don't use disc brakes. They will be in the way of your rear sprocket. I use V-brakes and they work fine. Which I believe are the same as cantilever brakes.
Coaster brakes as far as I know will work but you will need to remove them and modify them to fit on with the sprocket.
Please no, those rubber mounts only lead to more problems than not. Closing in on a month since he's been last seen probably not interested in help anymore..
 




Joined
Feb 6, 2017
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#6
First of all, I hope you know that the fenders on beach cruisers are death traps! Either get rid of them or search on this forum where you can brace them better or else you're risking injuries and possible death.
 

crassius

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#7
I like to build 7-speed cruisers. A reasonably simple build, and the cantilever brakes work OK. Except for a bit of spacing on the front mount, and some bending on the rear fender to clear chain, the build can be done with just the standard parts in the kit. Fenders should also have new mounts to hold up to the vibration of the motor.
 

5-7HEAVEN

Active Member
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Jun 22, 2007
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#8
Before I installed a suspension fork onto my Diamondback cruiser,
all my oranges would bounce outa my front basket at 15mph.

Hitting potholes at 20mph was horrific.:(

JMO, I'd rather have my front suspension fork than my engine.

It's relatively easy to retrofit a mountain bike suspension fork onto your
cruiser frame.

Find one with disc brakes!

That's if you can find the right donor bike.

First, determine the length of your head tube (frame) and
diameter of the steerer tube on your cruiser bike.

Measure your head tube. That's the part of the frame that your fork lives in.

Then mark the position of your cruiser bike's handlebar in reference to your frame.
That way, you can reinstall your fork in its exact previous location.

Loosen the mounting bolts of the handlebar stem.

Have someone help you pull the frame up from your fork a few inches.
You don't have to completely remove the fork yet.

Stick a measuring caliper between the top of the fork and the bottom of the frame.

Measure the diameter of the steerer tube; It should be 25.4mm(1") or 28.6mm(1.125").

Measure the diameter of the steerer tube at its base.
It should be 26.4mm or 27mm on a 1" tube.

If your cruiser frame's tube is 25.4(1") diameter,
you'll have difficulty finding a mountain bike donor with the correct-sized fork.
You might have to buy a 1" suspension fork from a bike shop or ebay.

If your cruiser fork's steerer tube measures 28.6mm (1.125"), you're in luck.
Most mountain bike forks measure to be 1.125" diameter.

The first thing to do is measure from the bottom of the donor bike's
head tube(or the top of its fork) to the top of the steerer tube,
where the cap is.

Your donor bike's steerer tube extends well past its head tube.

You need to decide if you're going to keep your cruiser bike's original handlebar,
or if you're gonna use the mountain bike's handlebar.

JMO, it's much easier if you use everything from the mountain bike
to retrofit onto your cruiser bike.

If the gods smile upon you, the head tube from the donor bike will be the same
or longer than your cruiser bike.

If it's longer, add spacers between the bike stem and
the top of your cruiser bike's head tube.

If the new fork's tube is short, you'll have to
use your cruiser bike's stem and handlebar.

Take the old fork and the donor fork to the local bike shop.
Have them cut it the same length, PLUS an extra 1/4"(just in case).

Reinstall everything, line up the handlebar and the mark on the frame.

Install the wheel, brake lever, cable and adjust your brakes.

Salvage the fork, brake, wheel, bearings and spacers on the fork,
everything on the handlebar except the shifter.

If your cruiser bike has 28.6mm(1.125"),
everything should bolt into place.

If the handlebar sits too high, remove a few spacers
and trim the donor fork to fit.

If you do it this way, you don't have to thread the steerer tube.

Good luck.

If you visit your local bike shop, and you tell them what you're trying to do,
they might look at you funny, and recommend you buy
a comfort bike or a mountain bike.
 
Last edited:

Joined
Jul 14, 2017
Messages
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#9
Wow ok. What kind of problems do they cause?
Wow guys I didn't see your first response... my bad.

I'm still here, whenever I get a chance.
Thanks for the response, I appreciate it. I'm not too sure on the rubber mounts but if "Frankenstein" thinks it's a bad idea, I will keep that in mind.
I'm not even thinking of the engine just yet, I'm mostly trying to get it ready for when I do put it on!
Things like brakes and forks with shocks. =)

Thanks guys,
-NOOB
 

Joined
Jul 14, 2017
Messages
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#10
Please no, those rubber mounts only lead to more problems than not. Closing in on a month since he's been last seen probably not interested in help anymore..
Frankenstein, I will keep your advise on the rubber mounts in mind, I still haven't sealed the deal will the motor yet. I just cant afford it yet! $$

Thnaks,
-NOOB
 
Last edited:

Joined
Jul 14, 2017
Messages
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#11
First of all, I hope you know that the fenders on beach cruisers are death traps! Either get rid of them or search on this forum where you can brace them better or else you're risking injuries and possible death.
Thanks for this post, potato.
I will keep this in mind...
As it stands, my cruiser doesn't have any fenders. I just currently ride while trying to keep a look out for streams and puddles. I definitely haven't ridden in the rain yet. lol.
I was thinking about getting some smaller fenders in the future, maybe even the plastic ones, I think they're called mud guards? Only because I don't want my back to get splattered if there's water on the floor.
For now I've got a cargo rack on the back and that should keep my back clean in the meanwhile.
This reminds me... I've got a collapsible side basket on the back and I don't know how this will hold up when I do retrofit an engine on.
I'm a student and I want to use this for school. I was thinking of "panniers" but haven't gotten around to it yet $.

Thanks again,
-NOOB
 

Joined
Jul 14, 2017
Messages
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1
#12
I like to build 7-speed cruisers. A reasonably simple build, and the cantilever brakes work OK. Except for a bit of spacing on the front mount, and some bending on the rear fender to clear chain, the build can be done with just the standard parts in the kit. Fenders should also have new mounts to hold up to the vibration of the motor.
Thanks, crassius. I think I would at least like to get the front brake disc and if I ever modify the rear it would probably be for looks only. I dont know how much modification is needed with the short fenders/mud guards, but I guess I will find out once I buy them.
It should not need too much bending since I was going to try and use a jackshaft kit so that I could use just the same drive chain currently being used fot the bicycle.
I heard that it needs to have a modified crank sprocket to work?

Thanks again,
-NOOB
 



Joined
Jul 14, 2017
Messages
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#15
Before I installed a suspension fork onto my Diamondback cruiser,
all my oranges would bounce outa my front basket at 15mph.

Hitting potholes at 20mph was horrific.:(

JMO, I'd rather have my front suspension fork than my engine.

It's relatively easy to retrofit a mountain bike suspension fork onto your
cruiser frame.

Find one with disc brakes!

That's if you can find the right donor bike.

First, determine the length of your head tube (frame) and
diameter of the steerer tube on your cruiser bike.

Measure your head tube. That's the part of the frame that your fork lives in.

Then mark the position of your cruiser bike's handlebar in reference to your frame.
That way, you can reinstall your fork in its exact previous location.

Loosen the mounting bolts of the handlebar stem.

Have someone help you pull the frame up from your fork a few inches.
You don't have to completely remove the fork yet.

Stick a measuring caliper between the top of the fork and the bottom of the frame.

Measure the diameter of the steerer tube; It should be 25.4mm(1") or 28.6mm(1.125").

Measure the diameter of the steerer tube at its base.
It should be 26.4mm or 27mm on a 1" tube.

If your cruiser frame's tube is 25.4(1") diameter,
you'll have difficulty finding a mountain bike donor with the correct-sized fork.
You might have to buy a 1" suspension fork from a bike shop or ebay.

If your cruiser fork's steerer tube measures 28.6mm (1.125"), you're in luck.
Most mountain bike forks measure to be 1.125" diameter.

The first thing to do is measure from the bottom of the donor bike's
head tube(or the top of its fork) to the top of the steerer tube,
where the cap is.

Your donor bike's steerer tube extends well past its head tube.

You need to decide if you're going to keep your cruiser bike's original handlebar,
or if you're gonna use the mountain bike's handlebar.

JMO, it's much easier if you use everything from the mountain bike
to retrofit onto your cruiser bike.

If the gods smile upon you, the head tube from the donor bike will be the same
or longer than your cruiser bike.

If it's longer, add spacers between the bike stem and
the top of your cruiser bike's head tube.

If the new fork's tube is short, you'll have to
use your cruiser bike's stem and handlebar.

Take the old fork and the donor fork to the local bike shop.
Have them cut it the same length, PLUS an extra 1/4"(just in case).

Reinstall everything, line up the handlebar and the mark on the frame.

Install the wheel, brake lever, cable and adjust your brakes.

Salvage the fork, brake, wheel, bearings and spacers on the fork,
everything on the handlebar except the shifter.

If your cruiser bike has 28.6mm(1.125"),
everything should bolt into place.

If the handlebar sits too high, remove a few spacers
and trim the donor fork to fit.

If you do it this way, you don't have to thread the steerer tube.

Good luck.

If you visit your local bike shop, and you tell them what you're trying to do,
they might look at you funny, and recommend you buy
a comfort bike or a mountain bike.
Thank you 5-7, for your exstensive description. I will try to make sense of it all and hopefully the "gods will smile upon me" and I will have the most compatible forks on my bike.
You said this: "Measure the diameter of the steerer tube; It should be 25.4mm(1") or 28.6mm(1.125").
Measure the diameter of the steerer tube at its base.
It should be 26.4mm or 27mm on a 1" tube."
I got a little confused on this because you gave 4 different measurements.
The "steerer tube" is attached to forks correct?

I remember I took apart a bike once and I had to remove the cups/races at the top and bottom of tube.
Do I have to do that in order to make my measurements?

You are right about the "local" bike shop, I tried to tell them that I wanted some rims that had disc brakes on them that were for a 7 speed.
They showed me a pair of rims that were the quick release type, without the gears, that were compatible to the cassette type gears.
I have the freewheel type gear on my rear rim that I was hoping I could transfer over to the new rim.
Also I was thinking that the quick release type of axle might be less strong than a conventional type, for motorized purposes?

Thanks again,
-NOOB
 





Joined
Jul 14, 2017
Messages
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#20
But a great one nonetheless.

Yes you'll need a new crankset which usually comes as part of the kit, have you decided on which type of engine you'll use, 4 or 2 stroke?
Frankenstein, thanks for your approval.
I called one of the motorized bike part websites not long ago and asked a some questions...
At first I really would've liked to put a 4 stroke for power and no mess fueling, but I was thinking about how big it would be underneath me, I would also need to fit a "transmission" of some sort.
The now "more convenient for me" 2 stoke would have more get-up-and-go, is smaller and has the "transmision" internal. Yes it makes more noise but I figure I could just put a longer muffler. I also heard the 2 strokes were easier compatible for the jackshaft kit.

How does all of this sound to you? PLease tell me.

Thanks,
-NOOB
 


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