DC Pk Ripper Reviews

[atlantis]

Hi !

http://www.sneakerfiles.com/2009/10/12/dc-x-se-pk-ripper-2010-fixed-gear/

I am keen on buying this bike, and needed your expert advice for the same.

Please let me know about the quality and durability of the components.

I ride a 49 cm road bike and 15" hybrid, the Ripper in stock is the 49 cm, is this the correct frame size for me.

I plan to ride the freewheel mostly , since it is a flipflop hub.


I have not ridden a single speed in some time, and would like to know your inputs, towards a first time single speed rider.

Thanks in advance

 

[alfeng]

FWIW. From what 'I' can see, the bike is NOT worth $1000(US) unless you are planning on making a fashion statement with the bike ...

• BTW. I didn't see any of the supposedly wonderful specs which the article's writer gushed about ...

FYI. ANYONE can piece together a better SS bike for less ...

• by either starting with a DROP BAR Single Speed ( e.g., Bianchi PISTA) and putting your own BMX handlebars on the bike ...
• Or, by starting with any of many other generic SS bikes which are available for $200(US), or more ...
• Or, taking the Road-or-MTB frame of your choice & having a wheelset made with some WHITE INDUSTRY ENO hubs ...
• Or, simply use a chain tensioner OR half-link instead of the ENO hub.

With FLAT handlebars, if you want approximately the same riding position as with DROP handlebars, then you will want the frame's top tube to be 3-to-4 cm longer than on your Road frame ... so, if your Road bike's frame has a 52cm top tube, then you would probably want a frame whose top tube is about 55cm UNLESS you want a more upright riding position ...

Of course, changing the stem length AND the handlebar's rise (of course, BMX bars have more rise than the most extreme MTB handlebar) will affect the riding position.

Since you are looking at a 2010 (?) bike (THAT's a 3+ year old bike even if NOS), if the cost is going to be closer to $500(US), then "okay" ... again, if you are planning on spending anything close to $1000(US), then you should buy components you need & DIY.

 

[alfeng]

BTW. If you are going to use a Freewheel then you will want to add at least a FRONT brake ...

• the fork is drilled for a brake caliper of unknown reach, but I don't think that the frame is ...
• you will need to use "zip" ties or clamps to secure a rear brake cable's housing + drill the frame to accept a rear brake IF you want to add one ...
• the frame does not have water bottle bosses (THAT may-or-may-not be an issue, of course, for you)

 

[atlantis]

Thanks for the replies alfeng!

I am getting this bike at around 350 USD. Unfortunately single speeds and fixies are not the choice here in india, so I do not have any options.

Yes but i do have a bike which I can convert to SS but unfortunately does not have horizontal dropouts and the chain tensioner, cog/spacer route is not a satisfied single speed.

To be honest I am no fan of bmx's but I certainly would love to have a ss/fixie flipflop. Just so happened that this one is available.

What is your take on the components on this bike ? Cause all the options you have given me are great, but the availability of the components and spares is nil.

 

[alfeng]

First, at $350US, I'm all in on your buying that bike ... I can't say that it is a bargain at $350, but it is a pretty good price for what I can see unless the bike has been trashed.

FYI. The cranks are BMX cranks ... pretty high end CroMo if I recall OR they look like CroMo crankarms which typically cost about $200 (or, more?) ... possibly, they would have been THE crank of choice 6+ -- possibly 14+ (!¿! who can remember !?!), as in retro BMX, if there is such a thing -- years ago for BMX riders with deep pockets, but I don't think that competitive BMX riders use them any longer ....obviously, I don't know the crank arm length or if it is the length which YOU would prefer to use.

• I'm not sure about the frame's BB shell dimensions since my recollection is that the particular crank used some weird-to-me BMX-specific bearings/etc ... but, of course, it could be a 'standard' 68mm English BB shell.

I can't tell you anything about the wheels or their hubs ...

• after you buy the bike, let me know what they are

The frame's design is nice (e.g,. the single tube seat & chain stays joined to a B-stay), but other than the re-enforcing gussets at the head tube, it is more of a cosmetic issue (Nothing wrong with THAT!! BUT, again, it's more of an issue if you are making a fashion statement) ...

So, I while can understand the bike's original MSRP, but 'I' just do not think that it is worth $1000 for a normal rider ...

• again, it looks as though it would be a good deal at $350, so (IMO) you don't need to haggle for a lower price with the seller unless that is something that you want to do just to see if he will sell it for less

BTW. The ENO rear hub has an eccentric axle which allows you to adjust the fore-aft location of the hub by about a 1/4" (?) which is enough to tension the chain if the chain is the optimal length for the vertical dropouts. The problem with the ENO rear hub is that its MSRP/retail price is over $200US.

The half link is only available for 1/8" chains, AFAIK.

 

[atlantis]

Thanks Alfeng ! for your valuable opinion. Bike has come home. She is nice and a pleasure to ride. Although I am riding the freewheel combo 42 x 16, please let me know if this is fine, I am feeling a little load. Although riding any bike after a geared one is a load . Posture is not too stretched and with the Vittoria's coupled with the cromoly fork , road bumps are barely felt. The color is pleasant, although i had my reservations. The crank arms are around 160- 165mm and solid steel, nice clearance if I go fixie( turns). Rims are Velocity Chukker. All in all satisfied.

 

[alfeng]

Originally Posted by atlantis .

Bike has come home. She is nice and a pleasure to ride. Although I am riding the freewheel combo 42 x 16, please let me know if this is fine, I am feeling a little load. Although riding any bike after a geared one is a load . Posture is not too stretched and with the Vittoria's coupled with the cromoly fork , road bumps are barely felt. The color is pleasant, although i had my reservations. The crank arms are around 160- 165mm and solid steel, nice clearance if I go fixie( turns). Rims are Velocity Chukker. All in all satisfied.

FWIW. This may be stating the obvious, but gearing on a Single Speed is often BOTH a compromise AND a moving target, so to speak, based on the rider's conditioning or delusion (as is probably my case) as to what is viable for the terrain being ridden on -- level, hilly, mountain roads (!), off road, whatever ...

AND, what is best for one rider may be inappropriate for another ...

OR, what is best for a rider at the beginning of the "season" could-and-should be different for the end of the season (for people who don't ride all through the year) ...

Regardless, 42x16 (2.625:1) seems to be a really common presumption as far as gearing for read-to-ride Single Speeds ...

• for mostly cosmetic reasons, I have one bike (a vintage "Road" frame) set up with a 53t Chainring + a 20t Freewheel (2.65:1)
• and, another bike (a "Track" frame) is currently set up with a 48t Chainring + an 18t Freewheel (2.67:1)

The "first ride" of the season can certainly feel like a grind for me, now, whereas at one time a ratio of 2.6:1 would have been fairly wussy gearing for me.

• if you can't achieve the cadence you want with the 16t Freewheel, then you may want to replace it with a 17t or an 18t Freewheel (ACS makes a 17t Freewheel) ...
• alternatively, you can opt for a smaller Chainring -- although it isn't ideal, you can use a Road Chainring with a 1/8" chain ...
• if your Road bike's inner Chainring has the same BCD (probably not, but ...) then you can try it for a ride before you buy a new Chainring ...

• depending on where the rear wheel is located in the 'dropout', you may-or-may-not need a longer-or-shorter chain if you opt to change the Freewheel ...
• the thing about chain length is that you will probably want to figure out the tooth count range (if you plan to use more than one Cog-or-Freewheel size, that is) which you might eventually use so that the you won't have to use different chains for different combinations of Chainrings and/or Cogs/Freewheels ...
• on my "Road" frame, the wheel is near the middle of the 'dropout' -- that position allows me to hopefully fit an 18t Freewheel without any slack in the chain, but also a 22t ...
• on my "Track" frame, the wheel is near the front of the 'dropout' -- that positioning allows the same chain to be used if-or-when a smaller Freewheel-or-Cog is used ... or, if a smaller Chainring is used!?!

BTW. Glad you were able to buy the bike for (what I perceive to be) a good price & thanks for updating me on some of the bike's details.

 

[atlantis]

Went for a longish ride today ! And the ratios were comfortable so I will stick with the 42 x 16 for some time. I would appreciate it if you could tutor me as how do you calculate ratios ie how do you arrive at 2.625:1. And how do I compare it with other ratios.

 

[alfeng]

You are over-thinking the process of calculating the ratios ...

FWIW. I simply divided the number of teeth on the Chainring by the number of teeth on the Freewheel-or-Cog ...

'42' divided by '16' equals '2.625'​

'53' divided by '20' equals '2.65'​

'48' divided by '18' equals '2.67'​

.​

et cetera.

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[atlantis]

/img/vbsmilies/smilies/redface.gif Just curious how does this calculation help us ? or what do we compare it with ?

 

[alfeng]

I use the calculated ratio(s) as a benchmark which I can subsequently use if I want-or-need to change the gearing ...

• BUT, before that, when riding a multi-gear bike, it is possible for an individual to determine the probable gearing which will be ideal for a given individual which might work best for a given terrain ...

So, when I had it in my mind to set up a Single Speed bike for riding on Mountain (!) roads (altitude starting at ~6500 feet) & knowing the wussiest gearing (not counting the bail out gear) that 'I' needed, I set up a Single Speed with a 32t Chainring + a 22t ACS Freewheel (1.45:1) ...

​

THAT is close to a 39t Chainring + a 27t Cog (1.44.1) ... approximately the "lowest" gear which I need for some inclines (i.e., the 28t in an 11-32 Cassette) on the Mountain roads around 'here' ...

• again, there is no bail out gear & descents are basically a matter of coasting ...

So, if YOU were to choose one gear combination on your multi-gear bike & not shift during the ride along a particular course, you would know if that combination was the suitable for a particular Single Speed bike's setup ... if not, then you could use that combination as a benchmark against which you would EITHER try an easier gear combination OR a gear combination which would allow you to go faster (you can always get off the bike and walk it up inclines which are too steep for a particular gearing).

• of course, I have been passed by guys along the same roadways whose largest Cog appeared to be only a 22t or 23t (!!) with a standard 53/39 Crankset!
• having said that, a few (!?!) decades ago, the climb from Arroyo Hondo up to the Taos Mesa (~7000 feet altitude) with a 42t Chainring + the 19t Cog of a 6-speed Freewheel set me on the path toward trying to find appropriately low gearing ...

For your reference, here is the previously mentioned bike which has the 53t Chainring + 20t Freewheel (2.65:1) ...

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And, here is the bike with the 48t Chainring + 18t Freewheel (2.67:1) ...

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[atlantis]

This is fantastic ! A big Thank You. And those are some lovely bikes, adorable should I say !

Very much simpler now, the best I can do, is try to get my feelers on my geared bikes ( for a certain terrain) and apply the logic to a single speed. I stand to be corrected the crank is a 46t and not a 42t so thats a (2.875:1)

Just another question, this bike is equipped with a 17 tooth fixed cog ( sugino alloy is this good or cromoly better ?). I have never ridden fixed wheel. I would really appreciate if you could give the ins and out of riding fixed wheel. Speed is not a matter of concern now, just getting used to the start and stops and traffic riding. This bike did come with a rear brake, but somehow I feel the brakes would ruin the painted rims, any suggestions here ?

 

[alfeng]

Although the alloy Sugino cogs are "coated" ([COLOR= #ff0000]¿[/COLOR]nickel plated[COLOR= #ff0000]?[/COLOR][COLOR= #000000] BUT possibly just paint[/COLOR][COLOR= #ff0000]!?!)[/COLOR], they are definitely not as hard as any CroMo cogs will be ...

• the advantage of the Sugino Cogs is their weight + the Cog's carrier which allows for removal & replacement which only takes about a minute ([COLOR= #808080]presuming that the replacement cog is handy, of course![/COLOR]) ... you don't need a chain whip, you only need the tool to unthread & secure the Lockring ...
• a CroMo cog will probably last 3x longer than an alloy Cog
• the Sugino Cog's spline pattern is symmetrical, but due to indifference on my part I don't recall if the Cog has a shoulder on one side and/or how much a shoulder it might have ([COLOR= #808080]I think the Cogs did not have a shoulder since the carrier's 'lip' offsets the Cog[/COLOR]), so I don't know if it can-or-cannot be realistically installed inside-out to extend its useable STREET life ...
• I don't think that the Sugino Cogs are approved for Keirin "racing" -- but, they may be okay for lesser Velodrome racing -- which should give you a sense of their lack of robustness when compared wtih a steel Cog

FWIW. The BEST TIP which I can probably give you is to learn to do skid stops -- really, its a controlled drift where you end up coming to a stop. It's something that I learned to do in my misbegotten youth with coaster brake bikes AFTER I read about motorcycle riders drifting through corners ...

• for example, right foot at just above 9 o'clock & the left foot not on its pedal ... back pressure applied to the right pedal as you set your left foot on the ground & let the rear of the bike drift forward as you lean the bike in the direction of the foot you set on the ground ... I don't want to say that you are unweigting the rear of the bike as the rear drifts forward, but that is the net effect because you and the bike will be in different vertical planes ... use in an emergency when the front brake, alone, won't stop your forward momentum! Personally, 'I' never got used to setting my right foot down -- obviously, it would probably be better for me if 'I' could execute a skid stop with either foot ... as it is, you may never need to use the technique, but better to know it than to end up with your face planted in the back-or-front-or-side of a vehicle/whatever ...
• IMO, a great tip which someone observed & mentioned two-or-three (?) months ago in another thread in this Forum was to scrub downhill speed by using a similar technique -- essentially, [COLOR= #0000ff]drifting[/COLOR] ... but, without necessarily planting your lead foot ([COLOR= #808080]at least, as I understood it when I read it[/COLOR]) ... possibly also as I understood it, the technique is sort of akin to skiing VERY steep terrain where your skis basically pivot like windshield wipers as you try to maintain control & not tumble forward!
• Regardless, the caveat to the technique is that rear tyre wear will be fairly extreme if the technique is implemented with any frequency ... so, a robust touring tyre could be advised for the rear wheel.

Regardless, I think that you definitely want to learn to anticipate stop lights & stop signs AND other moving traffic + pedestrians & stray animals ... the same road hazards you might encounter on your normal rides but without the (dis-)advantage of coasting!

Unfortunately, I do not have any recommendations for saving the painted finish where the brake pads make contact with the rims ...

 

[alfeng]

BTW. Just to clarify -- this may be stating the obvious and/or hopefully makes sense -- because your feet will be going around with the pedals, that you apply the back pressure AND momentarily drift when the trailing foot reaches just above the horizontal ...

 

[atlantis]

HI !
Just rode a 26" tyre size fixie and was all over the place, I weigh approx 77 kg, but there was no way that I could get the demon to stop. Alas I would have to put the fixie rides to another day.

Alfeng ! I was just going through the specs, and saw that the axle nuts are alloy. What is your opinion with regard to this ?

 

[alfeng]

Originally Posted by atlantis .

Just rode a 26" tyre size fixie and was all over the place, I weigh approx 77 kg, but there was no way that I could get the demon to stop. Alas I would have to put the fixie rides to another day.

Alfeng ! I was just going through the specs, and saw that the axle nuts are alloy. What is your opinion with regard to this ?

I have alloy WING NUTS -- mostly for cosmetic (i.e., "retro") reasons -- I had to re-tap them to fit the slightly larger diameter axle ...

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And, they certainly seem to be able to hold, but ...

Subjectively, I think that STEEL or chrome plated BRASS axle nuts are preferred ...

• nuts which come with Track hubs are NOT alloy ...

It's not that alloy nuts won't hold, after all, steel & titanium bolts are frequently threaded into alloy components (e.g., stems) ...

BUT, it is certainly easier to round the hexagonal surface ... so, 'I' would probably only tighten-and/or-loosen alloy nuts with a BOX wrench rather than an open ended or adjustable crescent wrench.

BTW. I guess that drifting is an art ... you probably need to practice doing the skid stops at really slow speeds, first, OR resign yourself to using the brake calipers -- really, it's a safety thing & using the brake levers-and-calipers is recommended ...

It's being able to effectively slow down which is the "trick" to riding Fixed, IMO.

 

[Ripperman]

I have recently bought a PK Ripper fixie. Crank was 46 and fixie cog was 17... replaced the fixie cog with a Shimano Dura Ace 13 teeth fixie. Installed new alloy road pedals and fixed Cristophe Zefal half toe-clips. Ride between 20 and 24 kms every morning. Lovely bike. I live in Pune. Moved from Mumbai a year back.