Mountain Bike Reviews Forum banner
1 - 7 of 7 Posts

·
Registered
Joined
·
698 Posts
Discussion Starter · #1 ·
I couldn't decide whether to put this into the youth section, the weight wienie section, or the 26er section so I decided to just throw it in the general section :lol:

My son is 10 and until recently rode a 24" Diamondback Insight 24 Hybrid bike. Main reason I bought that bike for him ~2-3 years ago was the low standover height and it was the lightest bike I could find in a 24". I threw on some old LX Rapid Fire Plus shifters cause he had a hard time shifting the grip shifters and he's been riding ever since.

It was good for gravel roads and around the neighborhood but the last 2-3 months he's been really getting into mountain biking and has me taking him on real trails. I put a triple on there to give him lower gearing and when I went to put wider more aggressive tires on there I found out the 24" tires are really 540 sized tires and off road tires in that diameter are very few and far between (Only one I found was a Kenda tires sold at wheelchair stores).

Instead of putting money into a bike he's about to outgrow my dad gave him his old Raleigh M50. It's a 15" size steel frame with a Girvin Vector 2 and old horseshoe style brake boosters on the front and rear. My son fits on it with good stand over height and can ride it comfortably.

The first ride on it with the added traction and with the suspension fork he was quite a bit faster at first but soon hit a wall and tired out quickly on the bike. We've done longer harder rides where he was ready for more after the ride but on the 26r he was miserable the last mile of the short 5 mile ride as he was getting gassed. Going from a 25.3# bike to a 31.8# bike was a huge change for a 78lbs kid and he really felt it by the end of the ride. Anyone one else face this when trying to transition a ~10 year old from a 24" to a 26-27.5"? Looking on Trek's web page most entry level bikes like the Marlin 5 (my son's dream bike for some reason) are around 32lbs so my dad's old bike seems about on par with what is currently out there.

I'm contemplating the knobby wheelchair wheels for the 24" (There is a chance the front won't fit). I tried moving some conventional 24" mountain bike wheels over to it but the brake bosses are too high and the brakes don't have enough adjustability to make up the difference. I'm also contemplating putting the 26" on a diet. Since I need to replace the old rubber anyways the first thing I did was weight the wheels:

Rear wheel (with cassette and QR) 1556g
Front wheel (with QR) 1018g
Tubes 202/185
R Tire 892 :eek:
F Tire 684

I seemed to recall 100g tubes being a thing a long time ago. Best found in a 5 minute googles was a 125g Maxxis ultralite tube. And good light weight tube advice that won't break the bank?

I remember thinking 15-20 years ago ~600g was a good weight for a tire. We do flowing type single track trails mostly clay and dead roots. Just looking at Nashbar I could get a ~600 gram tire from Michelin or Continental from $20-32. Any suggestions here?

So with just a tire change which needs to be done anyways I can probably knock off over lb of rolling weight which will be a good start. I'd like to knock another lbs or 2 as cheap as possible. 25.3# of his old bikes isn't realistic but if I could get it to 29lbs that would almost be splitting the difference between his old bike and the starting weight of this bike.

I could drop the Vector 2 as it's 3.8lbs (including the stem) for a rigid fork and knock off a lb but I doubt my son would like that. That's more of a last resort

I have no idea how much the steel frame weights but I imagine it has to be close to 5lbs going by the feel test. I've been contemplating vintage aluminum 26" frames thinking I might be able to get another lbs from a frame change. I've seen some old aluminum frames go pretty cheap and swapping parts is always a fun project.

I don't know what a good weight is for a set of wheels but I imagine whatever came on my dad's old bike were not light. Has the market on 26" wheels dropped enough that you can get some rim-brake light weight wheels cheap or do good wheel sets still command a premium?

I figure some of you know the state of the 26r market better than me. I don't really want to throw a lot of money at a old 26er bike but I'll throw $100 to have a fun weekend project for the son and I to get the bike closer to a manageable weight. Any suggestions on what to look at for the biggest bang/buck to try to knock another 1-2lbs off the bike?

 

·
Cycologist
Joined
·
10,081 Posts
I would lose the bar ends and get lighter tires. Depending on the gearing he uses, you could knock it down to a 1x. Not sure I would bother with lighter tubes. You could try a lighter saddle.

Has he ridden it more than once? Could be he was just so excited that he went out at too fast of a pace and burned himself out. Most riders aren't the weight weenies that they once were, my newest SS is heavier than my old one.
 

·
Registered
Joined
·
698 Posts
Discussion Starter · #3 ·
When I turned the bike right side up to put on my stand I heard a sloshing water sound. Pulled the legs off and found they had water in them. Free weight reduction! Driving 4 hours in a heavy rain storm much have gotten water in them.

I weighed the tires on my bike and took the lightest 2 tires of all 4 of ours and put them on his. Removed the bar ends (118g). She sits at 30.8lbs now so I knocked a whole pound off without much work.
 

·
Registered
Joined
·
1,644 Posts
Are the seat tube and handlebars aluminum or something heavier? Steel? Chromoly? It's possible to find reasonably priced aluminum bars and seat tubes. And you could modernize the bar by going a little wider.
 

·
Registered
Joined
·
698 Posts
Discussion Starter · #5 ·
Are the seat tube and handlebars aluminum or something heavier? Steel? Chromoly? It's possible to find reasonably priced aluminum bars and seat tubes. And you could modernize the bar by going a little wider.
The original seat tube was aluminum but welded itself to the frame and had to be cut out. Currently it has a seat and seatpost out of junker walmart kids bike that was given to us (now that thing was 38lbs!). It's steel with steel seat mounting hardware/clamps but only 366 grams because it's only 6" long. My too big to fit old Kalloy post was 270 grams so I can probably get 100 grams from just a cheap $20 Kalloy post. Saddle is 400 grams. Just found a saddle @ 275g on Amazon for just $16 that has good kid acceptance factor (aka looks cool). Should be another 200g+ for about $35.

Ordered some Maxxis ultra light schrader vale tubes. He's only 80lbs so pinch flats shouldn't be an issue. We don't run in thorny areas so I'm not worried there either. @127g each should be about 133g of weight savings. $11 on Amazon for two.

Handlebar is aluminum so I'm not going to mess with it.

The bottom bracket is creaking and probably needs to be replaced. Bikepedia says it's a LP26 so I'll probably throw a UN55 in there because I've always had a thing against the plastic BB retainer. I think the un55 is lighter so that will probably save a few grams. Looks like you can get a set of 1x cranks and a BB in the "new to me" style (non square taper I'm old remember) for just $40-50. Not sure of the quality but that seems like it would be an upgrade rabbit hole especially with the old 7 speed freehub and non-V brake LX shifters/levers.
 

·
Registered
Joined
·
2,076 Posts
It looks like you're squeezing him on there before he's ready going by the seat position...

How big of a tire can you fit on the old 24" hybrid?

flea-bay is a good place since 24" isn't so common:

https://www.ebay.com/itm/Goodyear-2...Replacement-Rim-2-to-2-125-Black/233284600446

https://www.ebay.com/itm/Schwalbe-H...Performance-Line-Addix-Performan/264205112785

https://www.ebay.com/itm/Vee-Tire-C...-Black-72tpi-Dual/303226586034?epid=552182381

https://www.ebay.com/itm/TB49307200...ng-Dual-Compound/123699315654?epid=1237917362

But you're right, weight can kill the fun for a kid.

Maybe also look for an XS/S 26er... since no one can possibly ride anything but 27.5 or 29 anymore :skep:

I put this together for my 11yo at the time. Number 2 is still riding it at 15, but to be honest it's too small for her, but it's only a school commuter...

https://forums.mtbr.com/families-riding-kids/2005-cdale-f800-re-build-my-11-yr-old-851395.html
 

·
Registered
Joined
·
698 Posts
Discussion Starter · #7 ·
It looks like you're squeezing him on there before he's ready going by the seat position...

How big of a tire can you fit on the old 24" hybrid?

flea-bay is a good place since 24" isn't so common:
Unfortunately those are 507 diameter wheels the hybrid came with 540's and those are impossible to find. When shopping for 540 sized tires the only places that carry them are wheel chair supply houses. I tried to fit a 507 on there and no dice.The Diamondback was a fantastic kids bike except for that fact.

He can stand over the bike with a little clearance (I would want more). He comfortably reaches all the controls and is in a good comfortable riding position. He probably needs another inch or two to fit on the bike better but that's one of the reasons I'm putting him on this one so he'll stop bugging me to buy him a new bike while he's still to small to fit on modern 27.5s.

 
1 - 7 of 7 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top