Why does riding a smaller road bike feel better?

Discuss light weight issues concerning road bikes & parts.
CAAD8FRED
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Joined: Mon Jun 18, 2018 10:52 pm

by CAAD8FRED

Also, besides aero and weight, is there a ride/geo/comfort advantage to riding a bike a size or two too small?

Shrike
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by Shrike

Snapped the chain a few mins after starting a ride at the weekend so rolled back and grabbed the missus’ bike which is a size down. Same bike. Just smaller frame and 3cm shorter stem.

Felt like a totally different bike. Felt faster and definitely has a sharper turning circle. I was expecting a slight difference here and there, but didn’t expect it to be so pronounced. First time I’ve ever ridden two of the same bikes back to back in different sides before so maybe that’s common, maybe not. Either way my bike feels like ass compared to it.

by Weenie


TobinHatesYou
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by TobinHatesYou

CAAD8FRED wrote:
Tue Feb 05, 2019 10:55 pm
Also, besides aero and weight, is there a ride/geo/comfort advantage to riding a bike a size or two too small?
Basically bikes in the 54-56cm range are neutral and in order to make a smaller bike, they have to slacken the HTA and/or increase the fork rake to maintain clearance for 700c tires. They also have to steepen the STA, but this doesn’t have a direct effect on handling. Slacker HTA and increased rake/trail result in a lazier steering feel...think chopper motorcycles vs superbikes. This is generally not considered an advantage to most, though some might appreciate the more stable feel. Bikes decrease in wheelbase down to a certain point, and then the wheelbase might actually increase for the smallest sizes to allow for tire/wheel clearance.

Traditionally smaller bikes have been stiffer, but recently manufacturers have gotten wise and changed lay-up schedules, tube thicknesses, etc. to add back some compliance into smaller bikes.

CAAD8FRED
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by CAAD8FRED

TobinHatesYou wrote:
Tue Feb 05, 2019 11:18 pm
CAAD8FRED wrote:
Tue Feb 05, 2019 10:55 pm
Also, besides aero and weight, is there a ride/geo/comfort advantage to riding a bike a size or two too small?
Basically bikes in the 54-56cm range are neutral and in order to make a smaller bike, they have to slacken the HTA and/or increase the fork rake to maintain clearance for 700c tires. They also have to steepen the STA, but this doesn’t have a direct effect on handling. Slacker HTA and increased rake/trail result in a lazier steering feel...think chopper motorcycles vs superbikes. This is generally not considered an advantage to most, though some might appreciate the more stable feel. Bikes decrease in wheelbase down to a certain point, and then the wheelbase might actually increase for the smallest sizes to allow for tire/wheel clearance.

Traditionally smaller bikes have been stiffer, but recently manufacturers have gotten wise and changed lay-up schedules, tube thicknesses, etc. to add back some compliance into smaller bikes.
When you say lazier do you mean easier to turn because smaller bikes feel snappier in handling to me.

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C36
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by C36

Difficult to answer since you can have 3 parameters that changes
- frame geometry: shorter wheel base and possible different fork rake that will impact how the bike handle. Those changes are not consistent among the bike manufacturer.
- rider position and weight distribution, here I see a lot more problems that benefits using “2 size smaller”. I recall Andy Schleck having issues descending and his bizarre weight repartition (hands waaay in front of front axle) was one of the possible explanation. Image
In the meantime Sagan had Imagea custom made cannondale supersix with super long top tube to minimise those issues.
The last two points were not an issue when we had custom made frames. But marketing teams convinced us that we can perfectly be positioned on 5 sizes when it’s just a way to save money.


Now if “two size smaller” really feel better (and if the contact points are EXACTLY the same)... I would either question the size that was initially considered as “the proper size”, or how the fitting was done.





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Dan Gerous
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by Dan Gerous

C36 wrote:
Tue Feb 05, 2019 11:39 pm
Now if “two size smaller” really feel better (and if the contact points are EXACTLY the same)... I would either question the size that was initially considered as “the proper size”, or how the fitting was done.
Agreed, if the smaller feels better, it's the other one that's probably too big (or poorly fitted).

AJS914
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by AJS914

I could fit either a 54S or a 52S in a Colnago. The reach/stack are almost the same. With the 52S I need a few spacers. I think that's a better tradeoff than a 54S with no spacers and not much seatpost showing. I rode a 54S Colnago and it just felt like a giant bike. The 52S feels more nimble.

Geoff
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by Geoff

With respect to the steering 'feel', at least some of the more stable feeling of a smaller frame is that you need a longer stem to get the same bar position. A 140mm stem seems to really slow-down the steering of the bike quite a bit.

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wheelsONfire
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by wheelsONfire

I really noted this jumping between MTB's.
Several years ago, i had a rather small Foil. It was much like you say, but it was not as funny descending on.
Perhaps it's time to check somethings out and order a custom frame?
Bikes:

Ax Lightness Vial EVO Race (2018.12.21)
viewtopic.php?f=10&t=156137
Paduano Racing Fidia (kind of shelved)
Open *UP* (2016.04.14)


Ex bike; Vial EVO D

Mr.Gib
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by Mr.Gib

TobinHatesYou wrote:
Tue Feb 05, 2019 11:18 pm
They also have to steepen the STA, but this doesn’t have a direct effect on handling. Slacker HTA and increased rake/trail result in a lazier steering feel...think chopper motorcycles vs superbikes.
Perhaps you mean fork offset which in combination with head tube angle creates trail. And it is this combination that in part creates steering feel. So it becomes very hard to generalize about how a smaller bike will handle just based on the typically slacker head tube angles.

To me it all comes down to how a bike responds to lean which throws a bit of a wrench into some conventional wisdom about geometry and handling. A bike with a slack 72.xx degree head tube and 43mm offset will have floppy, cumbersome, unstable steering while climbing and at slow speed. Turn it downhill and get it up to speed and will become a carving weapon with razor sharp handling that will turn in fast and really hook up (my Colnago ). Take another bike with a steep HTA 73.5 and a 43 mm offset and you have good low speed handling, and a bike that is very stable under power/not upset by pedaling action, but also a bike that just wants to go straight at speed and requires excessive lean in tighter curves (my Parlee). The high speed stability of the Colnago is superior despite its greater responsiveness to lean. By this reasoning a smaller Parlee might handle more like my Colnago.

All this runs against common understanding that more trail makes a bike sluggish. The question becomes sluggish in what situation? In the end I have come to conclude that you have to ride 'em to know what you are dealing with. The numbers never tell the whole story.
wheelsONfire wrote: When we ride disc brakes the whole deal of braking is just like a leaving a fart. It happens and then it's over. Nothing planned and nothing to get nervous for.

Broady
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by Broady

I went from 56 with 100mm stem to 54 with 120, couldn't be happier. Bike feels far better. That was with a pro bike fit too.

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Conza
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by Conza

I had a size smaller than I should have 52cm (dad's old bike that got warrantied) and went ahead with a pro fit to adjust (longer stem 120mm), 140mm drop - so very aero, and was great. Giant Advanced Defy.
Could not slam, because needed the stack height.

Slightly bigger bike, 54cm - not slammed - temp, but felt good. Merida Scultura 7000-E.

Now BMC Team Machine Disc 2018 - 56cm, which translated to 54cm - with the idea of slamming the stem / cut the fork - but pro bike fit indicated not necessary etc.

Initially felt like driving a jumbo jet. Still kinda do. I guess the heavier factor. 7.7kg now, vs - 6.99kg, and 7.2kg previously.
It's all about the adventure :o .

Karvalo
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by Karvalo

CAAD8FRED wrote:
Tue Feb 05, 2019 10:55 pm
Also, besides aero and weight, is there a ride/geo/comfort advantage to riding a bike a size or two too small?
It depends. Literally all of it depends.

What size do you normally ride, what size is 'smaller', what geo changes occur between those specific bikes, how does your position and/or setup differ between those bikes... there is just so much going on.

GothicCastle
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by GothicCastle

Conza wrote:
Wed Feb 06, 2019 11:50 am
...Giant Advanced Defy. Could not slam, because needed the stack height.

Now BMC Team Machine Disc 2018 - 56cm, which translated to 54cm - with the idea of slamming the stem / cut the fork - but pro bike fit indicated not necessary etc. .
If you look at the geometry charts for these two (if I remember correctly), they are noticeably different. The BMC should feel a little harder to initiate a turn, but should also feel more stable at speed.

bm0p700f
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by bm0p700f

Well if the bike is too small it should not feel better.

On a smaller bike you would need a longer stem or its not actually smaller. Perhaps the bike you have been riding is too big.

by Weenie


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