Considering titanium

[Wisco]

Hi folks,

So I recently installed a 1000watt 48v rear hub motor into my aluminum Nashbar frame touring bike. In many ways it is ideal. It has a big front rack for batteries, wide gear range, etc. But the fact that it is aluminum makes me nervous, and this was also my grocery/ riding around with the girlfriend bike. And although there is still some room for cargo, it is now heavy and sluggish when used without motor assistance.

That's not a big issue, but I am having second thoughts about my bike choice. The other conversion I considered was my Mongoose titanium DX 10.7 mountain bike. Despite the brand name, it's a quality frame with great components. http://www.bikepedia.com/quickbike/BikeSpecs.aspx?year=1999&brand=Mongoose&model=DX+10.7

I'm not really a mountain biker, so it mostly sits in the garage. Every year I think of selling it, but come on, it's titanium. I'd have to get creative to fit the battery pack, but otherwise it seems like a good choice. The purist mountain biker downstairs was scandalized that I'd consider it, but do you all see any concerns? I know ti is resilient and flexible (we once had a dented ti bike come into the shop and "heal" overnight). I'm not sure how much flexing I would see with the 1000 watts on it though.

My kit is acting up (discussed in another thread) and although I'm not sure it is a serious problem, I certainly have grounds for an exchange. I'm also a competent wheel builder, so I could lace my hub into the existing wheel.

Thoughts?

 

[Ykick]

If I ever ran across a large triangle frame in Ti22 for a decent price I'd be an extremely happy eBiker.

And btw, "creative"? Use a triangle bag my friend - practically the only decent way to haul battery packs.

 

[voicecoils]

Good idea. I ride a Ti frame ebike and love it. Strong, light, doesn't rust, no paint to scratch.

Don't leave it sitting around unused, electrify it!

 

[Wisco]

I knew you all would like this idea, I am returning my 700c kit and hope they will send me a 26. Titanium ebike, here I come!

 

[voicecoils]

I knew you all would like this idea, I am returning my 700c kit and hope they will send me a 26. Titanium ebike, here I come!

Cool.

While the Ti frame's dropouts are probably pretty strong, I'd still suggest using high quality rear-specific torque arms on both sides. Like these: http://www.ebikes.ca/shop/ebike-parts/torque-arms/torqarm-v4.html
Having a your rear axle nuts go loose and destroy Ti frame's dropouts would be very sad!

 

[Ykick]

Always torque arms. Even if dropout's strong material they may not be deep enough and axles often tend walk-out with insufficient fastener torque and/or washer fitment.

TA's are a damn good last line of defense if/when things go wrong. This thread had me browsing eBay last night - seems to be a good $500-$1000 Ti22 supply out there, hmm???

 

[Wisco]

Exchanging for the 26" will give me time to increase my battery pack and get/make proper torque arms. This ti frame also has an integrated dérailleur hanger, whereas my aluminum frame has removable.. Which would further weaken the connection.

I'm not generally one to go for exotic materials, but this bike was donated to a community bike shop I had spent years helping run. Fortunately I caught it before someone sold it for $50. I gave the shop a couple hundred cash and a lot of components. It was a nice reward for 1,000+ hours volunteering. And of course I checked the serial against stolen bike registries. Squeaky clean!

Sometimes I toy with the idea of peeling off the decals and sticking on the stickers wall-mart models have to reduce the theft risk (and increase the comedy value). Unfortunately bike thieves arn't likely to be fooled.

 

[Ykick]

I know the Chinese sales model doesn't always fit the situation but I rarely, if ever, buy laced motor wheels anymore. If you have wheel building experience it's much better and often easier to just do it yourself. 2.2-2.5" x 26" is close enough to 700c OD - motor winding isn't normally an issue. Saves a little in shipping box volume too if you can find a loose motor? Just a thought...

 

[Wisco]

I see a lot of references to broken spokes of the forum. Mine has very thick spokes by bicycle standards.. Is it a quality issue? I was actually pleasantly surprised at the even tension and trueness. Granted, I haven't put 100 miles on it yet..

 

[amberwolf]

I see a lot of references to broken spokes of the forum. Mine has very thick spokes by bicycle standards.. Is it a quality issue? I was actually pleasantly surprised at the even tension and trueness.

Even, but probably insufficient.

If you read the rest of the threads and posts about building/fixing wheels and spokes and whatnot, you'll find out why the problems happen.