Depending woes, new bike , less speed

[Escapee..]

Its like when I used to race Karts and motorbikes on tracks. Your fastest laps were often those that felt scrappiest and all over the place cause you were so busy. You came in cursing as you thought you had cocked it up but when you looked at the lap sheets you had done PB's.

 

Go figure. Lap sheets dont lie.

 

You may have got used to a feeling of speed, but that feeling may be slow.

 

I did the same - went from a Steel frames Merckx (wish i still had it) to a Carbon Trek 5500. I was half an hour slower in the Edenvale race and even my wife beat me.

 

I was gutted.

 

Tires, inflation, headwinds, temperature, humidity etc - all make a difference.

 

I dont think you can blame that on the bike...

[Maniax]

My father-in-law had a RC3000 with Alex rims.  We called it the Tank. It was a tank.  Massively heavy.  But it decended like a missile.  He now rides a carbon SIlverback space 1.  Decending is slower purely because it weighs a lot less, but his ave speed over distance is up, less fatigue, better ride quality, more joy.

 

Don't just judge your bike based on 1 part of a 1000 piece puzzle.

[KingTJ]

"2012 merida race 903 , Alu frame Tiagra group set. And often clocked 73-74kph on decents. Now I splashed on a giant txt advanced SL,and this thing decends like a pig"

 

"more performance\acceleration with my old bike Spez Venge Ultegra with Fulcrum 3.5 Racing wheels than my current Giant Propel SL"

 

is this coincidence   ? Maybe the manufacturer is  

[HBO]

I also recently changed from a Trek Madone 5.2 to a Spez Venge- same wheels and group setting. I've also lost considerable weight and on the same descents I am definitely faster.

 

On those fast downhills the bike feels also more "glued" to the road. Can't wait for them fast descents on 94.7.

[RockCoach]

Descending fast has more to do with aerodynamics and your body weight than anything else. Yes, weight of bike and rolling resistance of wheels will play a small part but are negligible in comparison.

 

So check the bar set ups of both bikes or work on your body position. Get your chin just about resting on your stem, elbows tucked and butt up in the air.

[Ryinc]

I think you need to do more tests, e.g. switch wheels on a friend's bike and vice versa. Roll down without pedalling with bike on both bikes etc. I would be highly surprised if it is simply the bike not being as fast down hills - my money is on something not right on the bike, wheels or setup.

[Martin PJ]

Is the new bike smaller? Bigger and longer bikes descend better, I think this is because you sit more in the middle on the bike, rather than above it.

 

The trend is to ride smaller bikes, but then you battle to keep up on the down hills. As long as you don't get dropped, that is the main thing.

[Paul Ruinaard]

Hmm

 

weight counts to some extent but a much larger factor is aerodynamics.

 

Look at a tandem - its not the weight that makes them faster its the fact that for the same frontal area you have got double the power (or close to it). I can tell you for sure as I have tried to descend behind Andrew Mclean in the past (when he was like a third of my weight and I was doubly as fast) and he just disappeared.

 

And I go downhill like a brick off a cliff.

 

Remember wind resistance increases at the square of speed and after 30kmh is the major factor you are looking at. 

 

Geometry can play a role in making a rider less aerodynamic on top of the bike, like an MTB versus a road bike. That is however pretty hard to evaluate without a wind tunnel and controlled tests.

 

My CX bike is significantly slower on the downhills than my road bike, probably owing to tires, inflation and rolling resistance. But its also significantly heavier.

 

So you have to equalise all that and test on the same day on the same descent to get close to comparison

 

You have too many factors here to realistically blame the frame manufacturer.

 

Extrapolating your hypothesis about it being frames then would all teams riding Giant be significantly slower on the descents than their Specialized and other counterparts in the Pro Peloton?

 

 

[Pure Savage]

I use Suikerbossie as a good test, with minimal wind and my training wheels on 64-67km/h no pedaling. "Race" wheels on GP4000s, 75-77km/h

 

Everything else identical on the Vegnge. (Same tuck and tummy tucked in)

[Brickleberry]

So some feedback. The frame is slightly smaller as the old bike was a 55cm the tcr is a M compact 53.5 I think.

 

Amashova seemed to prove I have rectified the issue. Took my headset apart cleaned and re greased and I put on a set of 44cm C to C bars rather Han the 42cm bars I had on. Happily hit 72kph down fields hill and felt stable. Also went down inchanga quite fast and I must say the bike felt amazing in the tight corners. Thanks for all the info and ideas.

[26er]

I'm wondering if anyone can explain or has some helpful info.So I uses to ride a 2012 merida race 903 , Alu frame Tiagra group set. And often clocked 73-74kph on decents. Now I splashed on a giant txt advanced SL, and this thing decends like a pig, I struggle to push past 60kph and even at that speed she feels very jumpy, and lacking control.Always imagined these better bikes would be even better in the decents but , it really doesn't seem great.Frame tcr advanced slCampagnolo vento reaction/ Easton circut wheelsUltegra 10speed

It's because you bought the Merida from me

I only sell fast bikes:)HaHaHa

[Brickleberry]

It's because you bought the Merida from me

I only sell fast bikes:)HaHaHa

For sure 26er , that bike was super fast and stable on downhills, but good old upgraditis gets us all in the end.

[26er]

It never stops hey..

Good place to start is to check out the wheels on the new bike...

Are they 100% true?Do the bearings run smooth?

Any play so they can catch the brakes by any chance?

[26er]

Do you still have my number?

Send me a pic..

I would like to see it..I am also on Giant these days..