Commuting - Trying to make my ride lighter - help needed. Rigid forks?

I ride a almost stock Dahon Matrix Lockjaw and it's kinda heavy. I'd like to shave some weight off of it.
http://www.dahon.com/us/matrix.htm
I'm an "agressive" commuter. I ride along with fast traffic. I carry it around folded and we have some nasty hills around, so weight is an issue. It's around 15kg right now.

My thoughts:

Handlebars - Already swapped for temp alloy flat + crappy bar ends. Does carbon make a noticeable difference in comfort? Because the 30g less wouldn't be worth the $.

Fork - thinking about swapping them with a rigid carbon fork. The difference would be around 1kg, which is a LOT. But I never rode carbon so I don't have a clue of how harsh the ride is. What do you think about this one?

http://cgi.ebay.com/09-Racing-Ultim-XC-MTB-Carbon-Disc-Only-Fork-516g_W0QQitemZ110406308355QQcmdZViewItemQQptZDesktop_PCs?hash=item19b4ba9203&_trksid=p3286.c0.m14&_trkparms=65%3A12%7C66%3A2%7C39%3A1%7C72%3A1205%7C240%3A1318%7C301%3A0%7C293%3A1%7C294%3A50

A fork like that would change the geometry a bit, making the front an inch or two lower. How does that affect handling and comfort?

Saddle and seatpost - Stock saddle is heavy and hurts my ass. Wouldn't mind riding a sporty saddle that's light and still hurts. Not changing the seatpost because of the pump, I need that.

Brakes - I think I could ride a v-brake on the rear wheel, while keeping the disc on the front one. Is it possible to use the rear caliper on a front wheel of another bike? What's the weight difference?

Tires - Those continental tires (1.6 65psi max actually, not those listed on the dahon website) are kinda heavy, 500g each. I could change those to kevlar kendas that weight around 220g and can be pumped up to 125 psi. Would the 125 psi + rigid fork be TOO uncomfortable?

What do you guys think I should do about it? Any other stuff worth replacing?

swap the dahon for the xootr swift.

done and done.

Just a few comments.

Carbon handlebars would be less harsh than alloy.

A carbon fork + high pressure tires is definitely going to have a harsher ride than 65 psi tires and a suspension fork. However, I ride on a carbon fork with high pressure tires all the time and am not bothered by it. The roads I ride on are pretty decent for the most part. If you ride on rough roads, it may not be the greatest. If you do get new tires, you'll probably be alright lowering the PSI to just over 100 for a smoother ride unless you're a bigger guy. Also look for tires with a higher TPI.

I'd be worried about a 2 inch shorter fork. Maybe some MTB guys who've gone to rigid forks have some input. You could try the mechanics forum too.

it sounds like you want a bike that is 20-25 pounds. for all the money you spend on almost pointless upgrades and they really won't make you that much faster. your bette off buying an old steel bike from the 80s, maybe 25pounds and making minor upgades like comfy saddle, new tires and such. your better off with two bikes or selling the mtb. either way you'd be better of spending money on a comfertable saddle, lighter wheels and a lighter crank, a compact double is really nice for road bikes.

my road bike came with a pair of kevlar kendas tires as stock, they squared off after only 1,500 miles. really bad tires imo. try a pair of Continental Grand Prix 4000s, i got mine for 27 dollars each on pbk months ago. they are wearing well, gripping in the corners and when wet, much faster than any mtb tire and they aren't to hash of a ride.

http://www.probikekit.com/display.php?cat=Continental%20Tyres

it sounds like you want a bike that is 20-25 pounds. for all the money you spend on almost pointless upgrades and they really won't make you that much faster. your bette off buying an old steel bike from the 80s, maybe 25pounds and making minor upgades like comfy saddle, new tires and such. your better off with two bikes or selling the mtb. either way you'd be better of spending money on a comfertable saddle, lighter wheels and a lighter crank, a compact double is really nice for road bikes.

my road bike came with a pair of kevlar kendas tires as stock, they squared off after only 1,500 miles. really bad tires imo. try a pair of Continental Grand Prix 4000s, i got mine for 27 dollars each on pbk months ago. they are wearing well, gripping in the corners and when wet, much faster than any mtb tire and they aren't to hash of a ride.

http://www.probikekit.com/display.php?cat=Continental%20Tyres

I think the problem is that he's got a folder and he wants it be lighter both for carrying and for riding.

Forgot to mention that I'm from Brazil and availability is an issue for a lot of stuff around here.
I'm not getting another bike, because I got a great deal on this dahon. Otherwise I wouldn't be able to afford it. Can't have 2 bikes, gotta be just one.

I know I can´t make the bike much faster with these upgrades, but it´s going to be faster uphill, right? With 1.0 high pressure tires it gets as fast as it can... right? My problem is not the speed, the speed is okay. The bike just feels a bit heavy and it's a hassle carrying it around because of that.

Is carbon strong enough to resist a pothole or a curb jump? And is it damping enough to ride comfortably over bumpy pavement? And then I could run 65psi front and 100psi back...

Is carbon strong enough to resist a pothole or a curb jump?

Yes.



And is it damping enough to ride comfortably over bumpy pavement? And then I could run 65psi front and 100psi back...

You mean you'd keep your existing front tire or try and run the Kenda at 65 psi?

I ride a skinny tired road bike most of the year. I do ride it over some rough patches and don't mind but if my entire commute was on bad roads I don't think I'd be happy. Smaller diameter wheels also ride rougher than larger diameter wheels so a 1" tire on a 26" wheel will not be as smooth as a 25 mm tire on 700c wheel.

Forgot to mention that I'm from Brazil and availability is an issue for a lot of stuff around here.
I'm not getting another bike, because I got a great deal on this dahon. Otherwise I wouldn't be able to afford it. Can't have 2 bikes, gotta be just one.

I know I can´t make the bike much faster with these upgrades, but it´s going to be faster uphill, right? With 1.0 high pressure tires it gets as fast as it can... right? My problem is not the speed, the speed is okay. The bike just feels a bit heavy and it's a hassle carrying it around because of that.

Is carbon strong enough to resist a pothole or a curb jump? And is it damping enough to ride comfortably over bumpy pavement? And then I could run 65psi front and 100psi back...

I can understand than way of thinking, however I would think about not upgrading a little bit more.

$170 for a fork (that might really screw up the fit), $80 for a seat, $60-70 for tires, $50 for brakes. If you sold your Dahon for $450-500 (is it a 2009?), and add in the money you wanted to use for upgrading, you would easily have a swift, plus some cash left over for a seat or a mini-pump.

People change their minds about bikes they bought all the time. Why try and dress up a pig? The bike you bought isn't working for you. Unload it and get the bike you really want (lighter and faster).

I can understand than way of thinking, however I would think about not upgrading a little bit more.

$170 for a fork (that might really screw up the fit), $80 for a seat, $60-70 for tires, $50 for brakes. If you sold your Dahon for $450-500 (is it a 2009?), and add in the money you wanted to use for upgrading, you would easily have a swift, plus some cash left over for a seat or a mini-pump.

People change their minds about bikes they bought all the time. Why try and dress up a pig? The bike you bought isn't working for you. Unload it and get the bike you really want (lighter and faster).

Not a bad suggestion... if he wants a Swift ;)

I can understand than way of thinking, however I would think about not upgrading a little bit more.

$170 for a fork (that might really screw up the fit), $80 for a seat, $60-70 for tires, $50 for brakes. If you sold your Dahon for $450-500 (is it a 2009?), and add in the money you wanted to use for upgrading, you would easily have a swift, plus some cash left over for a seat or a mini-pump.

People change their minds about bikes they bought all the time. Why try and dress up a pig? The bike you bought isn't working for you. Unload it and get the bike you really want (lighter and faster).

I can too understand your way of thinking. But I got the matrix for a GREAT price. There are no bikes you can find in Brazil as good as the matrix for the price I paid. The swift is just not possible for me. Anything bigger than a fork will get taxed at 60% (including shipping) at customs.

Don't get me wrong, I LOVE the matrix. I'd just like it to fit me better and be as light as possible, like I would with any bike. And those parts I'd replace on my matrix would go into a tandem I'm thinking about building.

If you want truly light get a carbon or alu road bike frame, carbon fork, and use high end components to build a single speed. Build a nice light pair of wheels to go with it, and you'll easily get down to less than 8kg without compromise. Your bike will be great for 'aggressive' riding, with fast dynamic handling and super fast response. You'll end up with something like this....

http://i187.photobucket.com/albums/x248/cyclaholic_album/cssfg07.jpg


I'm commuting on it with a backpack and I love it! My Surly LHT with fenders & gears is my bad weather ride.

I know I can´t make the bike much faster with these upgrades, but it´s going to be faster uphill, right?



Not so it matters, no. If you louse up the handling by removing a suspension fork the bike was designed around and spend big cash and get 2lbs off, then if you + bike weighed 200lbs before, then you'll get a 2% improvement in performance.



With 1.0 high pressure tires it gets as fast as it can... right?


No. Rolling resistance depends far more on the quality and type of the tyre compound than pressure. Playing with tyres could increase performance on the level quite a bit - especially effort and acceleration at lower speeds, say below 15mph.



My problem is not the speed, the speed is okay. The bike just feels a bit heavy and it's a hassle carrying it around because of that.


Fair enough.



Is carbon strong enough to resist a pothole or a curb jump? And is it damping enough to ride comfortably over bumpy pavement? And then I could run 65psi front and 100psi back...

Strength depends on the design of the fork more than the material. And the damping properties of carbon are a myth. Carbon fibre dampens vibrations quickly - it would make a poor tubing fork - but that's not the same as absorbing shock, which is a matter of stiffness versus flexibility, and a property of the overall fork design, not the material. (As a material, CF is notably stiff.)

Ok - looking at the bike now the link is working for me, this isn't a small wheel Dahon - so I would remove the fork and put a suitable rigid one in its place. Pedaling would be more efficient and some weight would be saved, but I wouldn't pay big cash for carbon.

I'd also put the bike on high quality slicks 1.25 to 1.6 slicks with latex tubes. You'd get lower rolling resistance, better handling, lower weight - and it would be cheap. If the bike is used only on roads you won't miss the suspension fork.

Is carbon strong enough to resist a pothole or a curb jump?

Only the first 20-30 or so... then the microscopic stress cracks start to merge together and it can fail catastrophically at any time...

Im using the Cadenza which has a similar Lockjaw frame with rigid Al forks. They are surprisingly comfortable, I was expecting a bit of harshness but maybe the 2" Big Apples do their job too well.

..It's around 15kg right now....

Lose 5kgs body mass, it's cheaper and you'll be faster from better fitness. Your bike will handle better from lower center of gavity too :thumb:

Only the first 20-30 or so... then the microscopic stress cracks start to merge together and it can fail catastrophically at any time...

:rolleyes: :crash: Was this supposed to be a joke or do you really believe it?

Lose 5kgs body mass, it's cheaper and you'll be faster from better fitness. Your bike will handle better from lower center of gavity too :thumb:

He wants the bike to be lighter so it's easier to carry.

Only the first 20-30 or so... then the microscopic stress cracks start to merge together and it can fail catastrophically at any time...

OMG! I think I hit my 30th pot hole last week. I'm doomed. :eek:

He wants the bike to be lighter so it's easier to carry.

So if you lose 5kg off your gut, that's not as good as paying $$ to lose 1kg on the bike. Don't the legs have an easier job when things are lighter by 5kgs instead of 1kg?

:rolleyes: :crash: Was this supposed to be a joke or do you really believe it?

The fact that you had to ask says a bit of something about the reputation of carbon for durability doesn't it?



Well, I Do believe that carbon has absolutely no yield strength; so that the buildup of cracks problem will eventually occur. I don't necesarially believe its after just 30 potholes though.

Lose 5kgs body mass, it's cheaper and you'll be faster from better fitness. Your bike will handle better from lower center of gavity too :thumb:

Excellent! It works wonders for running (and pull-ups and push-ups :)), too.

The fact that you had to ask says a bit of something about the reputation of carbon for durability doesn't it?



Well, I Do believe that carbon has absolutely no yield strength; so that the buildup of cracks problem will eventually occur. I don't necesarially believe its after just 30 potholes though.

people ride carbon forks on cyclocross race bikes... they definitely don't die after 30 bumps/potholes. there's also a few carbon mtbs and forks on the market. CF isn't really that fragile at all.

Spend your money on nicer wheels. Also, don't pump up your 1.6's to 125 if you'd like to keep your wheels.

So if you lose 5kg off your gut, that's not as good as paying $$ to lose 1kg on the bike. Don't the legs have an easier job when things are lighter by 5kgs instead of 1kg?

Sure, if the OP is a giant kangaroo and carries the Dahon in his pouch then losing 5kg off his gut would probably be better than 1kg off the bike. ;)

My guess is though that he carries the bike using his hands and that it's his upper body that's looking for some relief, - not really his legs.

The problem I have with posts that suggest people lose weight off their body instead of the bike are:

1. It's not always that easy

2. Believe it or not, some people are at a healthy weight already

3. Losing weight off your body doesn't necessarily give the same benefits (though there are plenty of other benefits)

4. Who says you can't lose weight off your body AND the bike ?

The fact that you had to ask says a bit of something about the reputation of carbon for durability doesn't it?


No. People believe all sorts of much stupider things about bicycle - eg that very stiff frames are faster than moderately flexible ones, and that narrow tyres must have less "friction" than wider ones and so make the bike go faster.




Well, I Do believe that carbon has absolutely no yield strength; so that the buildup of cracks problem will eventually occur. I don't necesarially believe its after just 30 potholes though.

I don't think that you understand what yield strength is or how it relates to fatigue failure; it is correct that cf has no yield strength, but incorrect to think this means it will fail from fatigue and aluminium, for example, won't. In fact aluminium handlebars on bikes used hard should regularly be replaced, because they can break without warning...