I would like to install a Nexus 7 speed hub on my 3G Newport with an AL frame. Is there a safe way to expand the rear drop outs on an AL frame?
Spreading an AL frame
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Follow these steps:
1-Use a 2x4 or small car jack to spread the dropouts wide enough to accommodate the Nexus 7. Go a few mm further out than you have to, b/c the metal will spring back.
2-Tie a string around the DS dropout, loop it around the headtube, and bring it back to the NDS dropout. Check alignment at the seat-tube; both sides of the string should be equidistant from the seattube.
3-Test fit the Nexus 7. Make adjustments as needed.
4- install the wheel and go for a test-ride.
5-Discover that the frame has cracked. After your injuries heal, scrap the beercan frame and get a nice steel ride.
6-Follow steps 1 thru 4 with the steel frame.
7-Leave the Al to the Miller High Life and enjoy the benefits of a ferrous lifestyle.
HTH!
-Rob
1-Use a 2x4 or small car jack to spread the dropouts wide enough to accommodate the Nexus 7. Go a few mm further out than you have to, b/c the metal will spring back.
2-Tie a string around the DS dropout, loop it around the headtube, and bring it back to the NDS dropout. Check alignment at the seat-tube; both sides of the string should be equidistant from the seattube.
3-Test fit the Nexus 7. Make adjustments as needed.
4- install the wheel and go for a test-ride.
5-Discover that the frame has cracked. After your injuries heal, scrap the beercan frame and get a nice steel ride.
6-Follow steps 1 thru 4 with the steel frame.
7-Leave the Al to the Miller High Life and enjoy the benefits of a ferrous lifestyle.
HTH!
-Rob
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I would have to agree w/B808 regarding alu frames. This cheap material, while interesting, is not really suited for bicycle frames unless you don't ride much or are very light weight. Aluminum has proven to be short-lived, while on the other hand, a 1930's-50's handmade brazed/welded steel frame may last a few lifetimes if cared for properly. What I recommend to any ratter is go with an OLD low-mile steel frame with no repairs. These USA-sourced frames are really comparable to hand-made custom steel frames today, and are a great base for any build...
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I admit I've "shunned conventional thinking" and have tweaked aluminum parts in the past. These have mostly been things like derailleur hangers, brake levers, seat rails, etc. I've yet to have one actually break on me, but the procedure was always done with the expectation that it could happen.
If you're asking if there is a truly risk-free method for doing this, then I'm afraid the short answer is "no." ...it's also the long answer.
If you're asking if there is a truly risk-free method for doing this, then I'm afraid the short answer is "no." ...it's also the long answer.
Bolt on a home made set of dropout extensions made of aluminum. They would also give you a few inches of wheelbase.
Bummer, I was hoping to add hand brakes & freewheel to my 3G. Next step, this weekend I'll see if the 4 speed Nexus hub I have fits. The 24" rear/26" front wheels and tires off my Dyno may look pretty cool.
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Thanks for the info. According to the interweb, taken from 3G wheel set spec.
"Rear drop out spacing should be 116mm and front 110mm."
From Shelton Brown's site.
https://web.archive.org/web/20130925001938/http://www.shimano.com/publish/content/global_cycle/en/us/index/tech_support/tech_tips.download.-Par50lparsys-0015-downloadFile.html/08) Hub Dimensions.pdf
Are O. L. D. and spacing the same thing? The smallest 3 speed hub is 120mm.
My 4 speed hub is model Nexus SG-4R35, 130mm. I would assume a no go.
"Rear drop out spacing should be 116mm and front 110mm."
From Shelton Brown's site.
https://web.archive.org/web/20130925001938/http://www.shimano.com/publish/content/global_cycle/en/us/index/tech_support/tech_tips.download.-Par50lparsys-0015-downloadFile.html/08) Hub Dimensions.pdf
Are O. L. D. and spacing the same thing? The smallest 3 speed hub is 120mm.
My 4 speed hub is model Nexus SG-4R35, 130mm. I would assume a no go.
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I´ve seen those specs on the 3G wheelsets, and a big part of the reason that I never ordered any is b/c the OLD specs seem off. Singlespeed coaster hubs tend to be 110mm; some (eg, new-production Sturmey-Archer S1C) are 116mm but normal KT HiStops (like the ones from the 3G wheels) are 110. No big deal; it´s easy enough to remove a few spacers and get´m back to 110; might need to redish. But, 110mm front? Aside from forks with thru-axles, the standard for traditional front spacing has been 100mm for, like, 40 years. No bike with normal axles has a 110mm front... unless 3G does. I´d always assumed it´s a typo.
¨Are O. L. D. and spacing the same thing?¨ Not exactly, but they are closely related. OLD= O.ver L.ocknut D.imension. This is the distance along the hub´s axle between the jamnuts (which are often referred to as locknuts...) ¨Spacing¨ refers to the distance between the bicycle frame´s dropouts, measured from the inner side of one dropout to the inner side of the other. The goal is for the OLD and the spacing to be the same number; what you´re dealing with now is how to make them match, when they don´t.
My best suggestion is to measure the spacing, both front and rear, on the frame itself. Take the wheels out and measure the space, in mm. I truly suspect that 3G messed up, but i hope it really is 116mm in the rear, as many of Sturmey-Archer´s three speed hubs are spaced at 116mm from the factory. They do make some that are 110mm spaced, but these are rim-brake only models, most often found with 28h drillings.
But yeah, in the end, if you physically measure your frame, that will give you a better idea of what drop-in options are available to you.
HTH
Thank You
