my denali build, maybe

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my denali build, maybe

Postby lurker » Wed Jan 10, 2018 1:50 pm

as i've mentioned elsewhere on the forum, i have a Kent GMC Denali in the large 25" frame. it is on the heavy side for a road bike, reputedly 29 or 30 lbs. i'll check at some point with my old imprecise bathroom scale.
weight, i believe, is not a critical factor except with regard to accelerating or climbing hills, but i think it is worthwhile to consider lightening the denali, in particular by substituting aluminum parts for steel. this thread is where i intend to collect information i believe useful to that purpose.
first, steel (8g/cc) is about 3 times heavier than aluminum (2.7 g/cc) per unit volume.
second, going over the bike with a magnet reveals that the front fork, crankset and handlebars are the most substantial steel components. allegedly significant performance can be gained by going to narrower, higher pressure tires but that's beyond the scope of what i'm after here right now. so what i'm planning to do is isolate the steel parts, weigh them, find suitable aluminum replacements and weigh them, thus giving an estimate of weight reduction available at reasonable cost. what's reasonable? your results may vary, but for me, no more than the initial cost of the bike, i.e. ~$160. it is, after all, a big box bike. i'm in no hurry to spend money so this is going to take some time. be patient.
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Re: my denali build, maybe

Postby jimmie65 » Wed Jan 10, 2018 5:23 pm

I would think handlebars would be the cheapest item to replace, especially if you are willing to buy used. I see aluminum dropbars for $20 or less on CL or at swap meets, even carbon bars for $50 or so.

The fork would be the most significant just based on volume. Is the Denali threaded or unthreaded?

I'd also look for a used wheelset. I assume the Denali is a 7-speed freewheel. Ought to be easy to find some used wheels for less than $100.
Current bbb bikes - Mongoose Beast, Iron Horse Yakuza 5.1, and an unknown fat BMX.
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Re: my denali build, maybe

Postby Tomcat65 » Wed Jan 10, 2018 5:32 pm

The Revo-Twist shifters on those bikes are all plastic, so they're fairly light, but those 3 piece handlebars are heavy. The problem is, those shifters will not work on a standard drop bar. One of the lightest and most affordable alternatives would be a stem mounted friction shift set-up.

Tires could be more of a weight saving than you think, and they could prove to be the biggest possible improvement in performance.

The only really dependable upgrade you can make on the fork, is to go carbon fiber. Aluminum forks are dependable for a while, but aluminum in a high stress situation like a fork, is more likely to fail than steel or carbon fiber. That's why you'll see aluminum forks on track bikes that aren't intended for the stresses of street use. Nashbar has a good deal on a carbon fiber fork with a strong aluminum steerer tube, but a fork plus anything else, is going to blow your budget.

At your budget, The most cost effective mods will be tires, handlebar/shifters, and you can find a light crankset that would fit within the budget.

And if you're like the rest of us, the budget goes out the window and there will be small parts and replacement parts along the way.

Aluminum is lighter per unit than steel, but it takes more aluminum to compare to the strength of steel, so the weight savings aren't always as dramatic as you might expect.
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Re: my denali build, maybe

Postby lurker » Wed Jan 10, 2018 8:52 pm

threaded fork i think. i'm just beginning to understand how profound my ignorance is.
for example, handlebars. there's a whole range of styles, and a whole range of sizes, and a variety of diameters. so it's likely to get complex in some details. i'm going to have to study up some.
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Re: my denali build, maybe

Postby jimmie65 » Thu Jan 11, 2018 5:09 am

I'd forgotten the Denali used MTB-style twist shifters. Yeah, replace those with stem mounted shifters. Here's an inexpensive set I've used - they will work with a 3x7 setup.
Current bbb bikes - Mongoose Beast, Iron Horse Yakuza 5.1, and an unknown fat BMX.
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Re: my denali build, maybe

Postby lurker » Thu Jan 11, 2018 10:09 am

jimmie65 wrote:I'd forgotten the Denali used MTB-style twist shifters. Yeah, replace those with stem mounted shifters.

i think there's a lot of MTB heritage in the denali. the frame geometry and wheels say roadbike to me, everything else looks MTBish. maybe it's really a hybrid. momma was a roadbike, daddy was a MTB, or vice-versa.
looking at how i actually ride when not actively shifting or braking, 80 or 90% of the time i'm on the top bar, 5 or 10 on the brake hoods, very little on the drops. why not build the bike to my style rather than the other way around? i'm thinking bar-mounted shifters and safety levers. dia-compe still makes safety levers, or there are "interruptor" brakes. so many decisions, ain't life grand?
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Re: my denali build, maybe

Postby wa_desert_rat » Sun Jan 14, 2018 7:14 am

I still ride my 1970's Peugeot PX-10 (which was a race-worthy bike back in the day) complete with Campagnolo down-tube-mounted friction shifters. This thing is 19lbs soaking wet and sports-car riding qualities. I put people on it who have never been on a bicycle like it before and they are amazed at how it rides.

Anyway, I'd go to a bike junkyard and find some down-tube shifters and use them. I managed thousands of miles shifting with them. :D
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Re: my denali build, maybe

Postby lurker » Fri Jan 19, 2018 8:16 pm

wa_desert_rat wrote:I still ride my 1970's Peugeot PX-10 (which was a race-worthy bike back in the day) complete with Campagnolo down-tube-mounted friction shifters. This thing is 19lbs soaking wet and sports-car riding qualities. I put people on it who have never been on a bicycle like it before and they are amazed at how it rides.

Anyway, I'd go to a bike junkyard and find some down-tube shifters and use them. I managed thousands of miles shifting with them. :D

i would like to see pics of that px.
coincidentally, tomorrow i'm going to the bike co-op. end of the month they're moving to another location a couple of blocks away, and i think my minivan might be useful to help them move to the new building.
while there, i'm hoping to pick up the peugeot i've been eyeing. i don't know the details, just that it's a peugeot and it has toe clips, but no wheels. it may prove more trouble than it's worth, but what's the worst that happens, i donate it back to the co-op? will report when i know more. meanwhile, it's been cold, monday we got 8" of snow, and it's just now melted enough to consider bicycling. and my computer crashed, corrupt boot sectors. bought a new computer, so far, so good.
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