Modifying a cassette for road racing events.

Oct 31, 05 19:55

Post #1 of 22 (3178 views)

The Mexican Triathlon Federation does not allow my 12 year son to compete if his bike's rollout (the distance the bicycle travels in one complete revolution of the cranks) is more than 6.7 m (about 264"). Because most triathlon events in the National Circuit take place in flat courses where gear changing is very limited, I just remove the smaller sprockets and replace them with spacers, leaving the Dual's cassette with some missing sprockets. No problem on this condition.

My son's experience in bicyle racing has been only in triathlons (lately more and more drafting events) and because of his times in the bike split he was chosen to participate in a series of road races to select our State team. He will use his Soloist for most of these trials that include from TTs to a good amount of climbing. The bike rollout for his age group has to be now no longer than 6.1 m (about 240"). This means that with his 53/39 chainring he can not use a sprocket smaller than size 19 to compete.

In my limited cycling experience (less than a year taking care of my 10 and 12 year old kid's racing cycles) I wonder if in this new road racing condition I should leave the cassette with spacers where the smaller (illegal) sprockets were before or if I should build a custom cassette to make the size 19 the smaller sprocket and fill the other spaces with larger sprockets to race with a full cassette.

Thanks beforehand for your important help.

Sergio

-------------------------------------------------------------------
Note: English is not my first language. Please read this translated post considering that.

Re: Modifying a cassette for road racing events. [Sergio Escutia] [ In reply to ]

Oct 31, 05 20:05

Post #2 of 22 (3165 views)

Perhaps an easier solution is to change the front cranks to compact cranks. Get rid of the 53-39, and you should be able to use most any cassette on the back.

The bigger question...your 12 year old son has both a Dual and a Soloist???

Umm...ok then....

Re: Modifying a cassette for road racing events. [Sergio Escutia] [ In reply to ]

Oct 31, 05 20:10

Post #3 of 22 (3155 views)

Either get a "junior gearing" cassette (14-?) or change out the chainrings. I do the latter.

___________________________________

http://irondad06.blogspot.com/

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Re: Modifying a cassette for road racing events. [Sergio Escutia] [ In reply to ]

Oct 31, 05 20:11

Post #4 of 22 (3152 views)

Oh... and use a gear-inch calculator http://www.panix.com/...cycal/cycal.30f.html to get the gearing right.

___________________________________

http://irondad06.blogspot.com/

http://irondad.blogspot.com/

Re: Modifying a cassette for road racing events. [Sergio Escutia] [ In reply to ]

Oct 31, 05 20:14

Post #5 of 22 (3150 views)

I've seen some cassettes where the disallowed gears were blocked by wrapping something (not sure what) around those cogs. Presumably you also have to adjust the limit screw on the rear derailleur to ensure you couldn't accidentally shift onto the blocked gears (i'm not even sure if you can adjust a limit screw that far). Either way, it would be cheaper than a new crank...

Post deleted by Administrator [ In reply to ]

Martin C

Oct 31, 05 20:32

Post #6 of 22 (3135 views)

Re: Modifying a cassette for road racing events. [GearGrinder] [ In reply to ]

Oct 31, 05 21:11

Post #7 of 22 (3105 views)

GearGrinder... I will take a closer look at the compact cranks available. Or maybe all I need to do is remove the bigger chainring and even the smaller sprockets from the 53/39 FSA Carbon Pro Team Issue crank :) Yes, he has at this time a 48 size Dual and a 51 size Soloist. The Soloist is a blue/white 2004 model I bought brand new a few weeks ago and I have been upgrading the components. The Dual is apparently getting too small for him as he has been growing very fast lately. Here is a photo of him on his Dual. (I have also been told that his seat is too high ;) )

Irondad... Thanks for the calculator link. I am pretty sure that the smaller sprocket should be a 19 using the 53 chainring. What sizes do you suggest for the other 8 sprockets? Because he will use the 19 sprocket most of the time and he can not use a smaller one, Should I leave at least a space empty to keep the chain straighter?

Nipsy and mc sac... I placed in the above cycle an Ultra High Density Polyethylene bushing made to order to act as a spacer in place of the missing sprockets and normal spacers. This also saves some weight.

Thanks to all for your helpful comments.

Sergio

-------------------------------------------------------------------
Note: English is not my first language. Please read this translated post considering that.

Re: Modifying a cassette for road racing events. [Sergio Escutia] [ In reply to ]

Oct 31, 05 21:15

Post #8 of 22 (3102 views)

All you need to do is replace the large chainring on the existing crank with a smaller one.

.

Tech writer/support on this here site. FIST school instructor and certified bike fitter. Formerly at Diamondback Bikes, LeMond Fitness, FSA, TiCycles, etc.
Coaching and bike fit - http://source-e.net/ Cyclocross blog - https://crosssports.net/ BJJ instruction - https://ballardbjj.com/

Re: Modifying a cassette for road racing events. [Sergio Escutia] [ In reply to ]

Oct 31, 05 21:25

Post #9 of 22 (3091 views)

If you change the chainrings as some suggest you will need to readjust and possibly reposition the front derailleur and adjust the front shifting cable. I'm somewhat surprised your twelve year old is able to fit adult 700c wheel bikes. In any case in the US, one can meet the rollout regulations by using a screwdriver and adjusting the low travel screw on the rear derailleur so that the rear shifter will not move to the smaller gears in back, but most juniors only have to limit one or two gears, not half or more of the cluster as you are describing.

Re: Modifying a cassette for road racing events. [fredly] [ In reply to ]

Oct 31, 05 21:25

Post #10 of 22 (3091 views)

fredly... Thanks a lot. I had in my hands the new FSA crankset and thinking about this possibility a few seconds ago. Seems that I will have to remove the larger chainring and place some spacers in place of the smaller one. Is this correct?

Thanks again. Great help.

Sergio

-------------------------------------------------------------------
Note: English is not my first language. Please read this translated post considering that.

Re: Modifying a cassette for road racing events. [Sergio Escutia] [ In reply to ]

Oct 31, 05 21:27

Post #11 of 22 (3087 views)

You have a lot of possibilities. Even with a 130 BCD crank you can get any chainring from 38 to 56 pretty commonly in one tooth increments. This way you could keep two chainrings on the bike for more versatility ( not forcing you to change chainrings and the front shifter/derrailleur adjustment all the time among other things...) Also since your kids are so young, you want to be careful to not let them try to push too big of a gear anyways, and having smaller gears carries just a small weight penalty.

Last edited by: SWoo: Oct 31, 05 21:28

Re: Modifying a cassette for road racing events. [SWoo] [ In reply to ]

Oct 31, 05 21:36

Post #12 of 22 (3076 views)

Swoo... The Dual is a 650c bike. The newer Soloist is a 700c. He is 167 cm tall at this time and growing fast. I will take a photo of him in the 51 size Soloist to get some comments on his position. It seems now as you and others suggest that I should make the change in the chainrings.

In M�xico using a screwdriver and adjusting the low travel screw on the rear derailleur so that the rear shifter will not move to the smaller gears in back is too risky as some judges allow this practice and some will not. To eliminate the chance of exposing my kids to an argument in this regard from an over enthusiastic father of a second place winner, I prefer to remove the sprockets from the cassette. :)

Thanks again to all.

Sergio

-------------------------------------------------------------------
Note: English is not my first language. Please read this translated post considering that.

Last edited by: Sergio Escutia: Oct 31, 05 21:47

Re: Modifying a cassette for road racing events. [Sergio Escutia] [ In reply to ]

Oct 31, 05 21:38

Post #13 of 22 (3072 views)

In Reply To:

The Mexican Triathlon Federation does not allow my 12 year son to compete if his bike's rollout (the distance the bicycle travels in one complete revolution of the cranks) is more than 6.7 m (about 264"). Because most triathlon events in the National Circuit take place in flat courses where gear changing is very limited, I just remove the smaller sprockets and replace them with spacers, leaving the Dual's cassette with some missing sprockets. No problem on this condition.

My son's experience in bicyle racing has been only in triathlons (lately more and more drafting events) and because of his times in the bike split he was chosen to participate in a series of road races to select our State team. He will use his Soloist for most of these trials that include from TTs to a good amount of climbing. The bike rollout for his age group has to be now no longer than 6.1 m (about 240"). This means that with his 53/39 chainring he can not use a sprocket smaller than size 19 to compete.

In my limited cycling experience (less than a year taking care of my 10 and 12 year old kid's racing cycles) I wonder if in this new road racing condition I should leave the cassette with spacers where the smaller (illegal) sprockets were before or if I should build a custom cassette to make the size 19 the smaller sprocket and fill the other spaces with larger sprockets to race with a full cassette.

Thanks beforehand for your important help.

Sergio

Are you sure about that rollout because plugging the numbers in gives me this showing you need a 34 tooth chainring: (is it 650 or 700?)

SP Shifting Pattern
CRxFW ChainRing x FreeWheel
GI Gear Inches
GIdf Percentage of increase between present GI value and the
next sequential GI value.
DI Distance traveled in INCHES in a single pedal rotation
diff Difference in INCHES between the present DI value and
the next sequential DI value.
DF Distance traveled in FEET in a single pedal rotation
displayed as FEET' INCHES.decimal_remainder"
PRPM Pedal Rotations Per Mile
RT Gear Ratios

Wheel Diameter: 26.70 inches
Gears: 34 12
---------------------------------------------------------------------------
SP CRxFW GI GIdf DI diff DF PRPM RT
---------------------------------------------------------------------------
1> 34x12 75.65 0.00% 237.66 0.00 19' 9.66" 266.60 1:2.83
---------------------------------------------------------------------------
SP CRxFW GI GIdf DI diff DF PRPM RT
---------------------------------------------------------------------------
This Form Created: November 01, 2005 : 00:31:13

___________________________________

http://irondad06.blogspot.com/

http://irondad.blogspot.com/

Re: Modifying a cassette for road racing events. [Sergio Escutia] [ In reply to ]

Oct 31, 05 21:46

Post #14 of 22 (3069 views)

The USCF rules are as follows:

1J6. Junior Gears. For Junior Men & Women, the authorized maximum chaingear ratio allowed in any road event (except cyclo-cross) is 7.93 meters (rollout 26'). [45x12 or 52x14 chain ring teeth]. Blocked gears will be allowed, except in National Championships. For track events the following limits shall be used: (10-14 years old � 21'3", 15-16 yrs � 21'9", 17+ yrs. - Unrestricted.) All tests for compliance (road and track) shall be done using the "roll-out method."

I think that follows international rules so you might double-check the rollout because it seems awfully short.

___________________________________

http://irondad06.blogspot.com/

http://irondad.blogspot.com/

Re: Modifying a cassette for road racing events. [Sergio Escutia] [ In reply to ]

Oct 31, 05 22:07

Post #15 of 22 (3053 views)

i stopped reading when i realized that a 12 year old has both a dual, and a soloist

that's just great

Re: Modifying a cassette for road racing events. [IronDad] [ In reply to ]

Oct 31, 05 22:10

Post #16 of 22 (3050 views)

The Soloist has a measured weel circumference rolling with my kid on top of the bike of 2116 mm (83.3" perimeter or about 26.5" diameter).

I agree that the rollout seems very short. I am pretty sure about the triathlon rollout but not so sure about the shorter road rollout. Let me double check the numbers.

Thanks again for your help.

Sergio

-------------------------------------------------------------------
Note: English is not my first language. Please read this translated post considering that.

Re: Modifying a cassette for road racing events. [whokid] [ In reply to ]

Oct 31, 05 22:17

Post #17 of 22 (3046 views)

In Reply To:

i stopped reading when i realized that a 12 year old has both a dual, and a soloist

that's just great

He has those two bikes but he also has to bring home a very nice report card to be able to ride them ;)

Best wishes,

Sergio

-------------------------------------------------------------------
Note: English is not my first language. Please read this translated post considering that.

Re: Modifying a cassette for road racing events. [IronDad] [ In reply to ]

Oct 31, 05 22:28

Post #18 of 22 (3040 views)

I can not find a link to the rulings of the Mexican Federation but here is a link from the Colombia Triathlon Federation that states the same 6.7 m rollout distance as in Mexico for the 12-13 year old age group. http://www.triathloncolombia.com/...s/reglamentacion.htm

I will try to check this number in road events calling their HQs tomorrow as it is very important figure.

Thanks again.

Sergio

-------------------------------------------------------------------
Note: English is not my first language. Please read this translated post considering that.

Last edited by: Sergio Escutia: Oct 31, 05 22:39

Re: Modifying a cassette for road racing events. [Sergio Escutia] [ In reply to ]

Oct 31, 05 23:00

Post #19 of 22 (3021 views)

Hi Sergio,

The juniors that I have worked with usually wind up with a 45 or 46x12, depending on the tires they use (you need to roll the bike out to b sure.)

UCI rules don't allow for blocking gears, but USCF rules do allow this (except for nationals as mentioned above.) You should, of course, check with your national federation, but my understanding is you need to meet UCI regs.

I would set the bike up with a 45/38 by 12/25 and call it good. This should be good for most any course.

..

Tech writer/support on this here site. FIST school instructor and certified bike fitter. Formerly at Diamondback Bikes, LeMond Fitness, FSA, TiCycles, etc.
Coaching and bike fit - http://source-e.net/ Cyclocross blog - https://crosssports.net/ BJJ instruction - https://ballardbjj.com/

Re: Modifying a cassette for road racing events. [fredly] [ In reply to ]

Oct 31, 05 23:22

Post #20 of 22 (3015 views)

fredly... A 45x12 with my kid's tires will give me a rollout of 7.9 m which according to the info posted by Irondad will be OK for any road event in the USA. I am sure that for triathlon in Mexico I need to be below 6.7 m (53x17 in my kid's bike) for the 12-13 year old age group. As I said before my kid does no road races but I doubt that the number allowed is even close to the 7.9 m allowed in the USA for 12 year old road racing. I will check tomorrow.

Thanks again

Sergio

-------------------------------------------------------------------
Note: English is not my first language. Please read this translated post considering that.

Re: Modifying a cassette for road racing events. [Sergio Escutia] [ In reply to ]

Oct 31, 05 23:37

Post #21 of 22 (3008 views)

Yup. My bad.

Get back to us with that roll out #, and I can run it through the software I have and give you the gearing possibilities.

.

Tech writer/support on this here site. FIST school instructor and certified bike fitter. Formerly at Diamondback Bikes, LeMond Fitness, FSA, TiCycles, etc.
Coaching and bike fit - http://source-e.net/ Cyclocross blog - https://crosssports.net/ BJJ instruction - https://ballardbjj.com/

Re: Modifying a cassette for road racing events. [fredly] [ In reply to ]

Nov 1, 05 10:41

Post #22 of 22 (2950 views)

I just got a confirmation that the roll out is 6.10 m or 240.1". This is to keep them from reaching higher speeds but I can only wonder what his cadence is going to be in some particular circumstances.

Maybe I should take a relativelly new 39 chainring from an FSA Gossamer crankset to replace the 53 chainring on the new FSA PRO Carbon crankset. I can then arrange a cog set starting with a 13 or 14 size sprocket wheel. I am sure that a bike with two 39 chainrings will look odd but in my limited experience I think this will help keeping a good chainline.

Thanks again to all for your comments.

Sergio

-------------------------------------------------------------------
Note: English is not my first language. Please read this translated post considering that.

Last edited by: Sergio Escutia: Nov 3, 05 17:29

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